diff --git a/ext/bg/background.html b/ext/bg/background.html
index 90a56024..3b37db87 100644
--- a/ext/bg/background.html
+++ b/ext/bg/background.html
@@ -16,11 +16,13 @@
         <script src="/bg/js/api.js"></script>
         <script src="/bg/js/audio.js"></script>
         <script src="/bg/js/backend-api-forwarder.js"></script>
+        <script src="/bg/js/conditions.js"></script>
         <script src="/bg/js/database.js"></script>
         <script src="/bg/js/deinflector.js"></script>
         <script src="/bg/js/dictionary.js"></script>
         <script src="/bg/js/handlebars.js"></script>
         <script src="/bg/js/options.js"></script>
+        <script src="/bg/js/profile-conditions.js"></script>
         <script src="/bg/js/request.js"></script>
         <script src="/bg/js/templates.js"></script>
         <script src="/bg/js/translator.js"></script>
diff --git a/ext/bg/js/api.js b/ext/bg/js/api.js
index f32b984f..474fe604 100644
--- a/ext/bg/js/api.js
+++ b/ext/bg/js/api.js
@@ -140,7 +140,10 @@ async function apiCommandExec(command) {
         },
 
         toggle: async () => {
-            const optionsContext = {depth: 0};
+            const optionsContext = {
+                depth: 0,
+                url: window.location.href
+            };
             const options = await apiOptionsGet(optionsContext);
             options.general.enable = !options.general.enable;
             await apiOptionsSave('popup');
diff --git a/ext/bg/js/backend.js b/ext/bg/js/backend.js
index 3839da39..4068b760 100644
--- a/ext/bg/js/backend.js
+++ b/ext/bg/js/backend.js
@@ -23,7 +23,8 @@ class Backend {
         this.anki = new AnkiNull();
         this.options = null;
         this.optionsContext = {
-            depth: 0
+            depth: 0,
+            url: window.location.href
         };
 
         this.isPreparedResolve = null;
@@ -173,7 +174,40 @@ class Backend {
         if (typeof optionsContext.index === 'number') {
             return profiles[optionsContext.index];
         }
-        return this.options.profiles[this.options.profileCurrent];
+        const profile = this.getProfileFromContext(optionsContext);
+        return profile !== null ? profile : this.options.profiles[this.options.profileCurrent];
+    }
+
+    getProfileFromContext(optionsContext) {
+        for (const profile of this.options.profiles) {
+            const conditionGroups = profile.conditionGroups;
+            if (conditionGroups.length > 0 && Backend.testConditionGroups(conditionGroups, optionsContext)) {
+                return profile;
+            }
+        }
+        return null;
+    }
+
+    static testConditionGroups(conditionGroups, data) {
+        if (conditionGroups.length === 0) { return false; }
+
+        for (const conditionGroup of conditionGroups) {
+            const conditions = conditionGroup.conditions;
+            if (conditions.length > 0 && Backend.testConditions(conditions, data)) {
+                return true;
+            }
+        }
+
+        return false;
+    }
+
+    static testConditions(conditions, data) {
+        for (const condition of conditions) {
+            if (!conditionsTestValue(profileConditionsDescriptor, condition.type, condition.operator, condition.value, data)) {
+                return false;
+            }
+        }
+        return true;
     }
 
     setExtensionBadgeBackgroundColor(color) {
diff --git a/ext/bg/js/conditions-ui.js b/ext/bg/js/conditions-ui.js
new file mode 100644
index 00000000..a6f54a1c
--- /dev/null
+++ b/ext/bg/js/conditions-ui.js
@@ -0,0 +1,326 @@
+/*
+ * Copyright (C) 2019  Alex Yatskov <alex@foosoft.net>
+ * Author: Alex Yatskov <alex@foosoft.net>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+
+class ConditionsUI {
+    static instantiateTemplate(templateSelector) {
+        const template = document.querySelector(templateSelector);
+        const content = document.importNode(template.content, true);
+        return $(content.firstChild);
+    }
+}
+
+ConditionsUI.Container = class Container {
+    constructor(conditionDescriptors, conditionNameDefault, conditionGroups, container, addButton) {
+        this.children = [];
+        this.conditionDescriptors = conditionDescriptors;
+        this.conditionNameDefault = conditionNameDefault;
+        this.conditionGroups = conditionGroups;
+        this.container = container;
+        this.addButton = addButton;
+
+        this.container.empty();
+
+        for (const conditionGroup of conditionGroups) {
+            this.children.push(new ConditionsUI.ConditionGroup(this, conditionGroup));
+        }
+
+        this.addButton.on('click', () => this.onAddConditionGroup());
+    }
+
+    cleanup() {
+        for (const child of this.children) {
+            child.cleanup();
+        }
+
+        this.addButton.off('click');
+        this.container.empty();
+    }
+
+    save() {
+        // Override
+    }
+
+    isolate(object) {
+        // Override
+        return object;
+    }
+
+    remove(child) {
+        const index = this.children.indexOf(child);
+        if (index < 0) {
+            return;
+        }
+
+        child.cleanup();
+        this.children.splice(index, 1);
+        this.conditionGroups.splice(index, 1);
+    }
+
+    onAddConditionGroup() {
+        const conditionGroup = this.isolate({
+            conditions: [this.createDefaultCondition(this.conditionNameDefault)]
+        });
+        this.conditionGroups.push(conditionGroup);
+        this.save();
+        this.children.push(new ConditionsUI.ConditionGroup(this, conditionGroup));
+    }
+
+    createDefaultCondition(type) {
+        let operator = '';
+        let value = '';
+        if (this.conditionDescriptors.hasOwnProperty(type)) {
+            const conditionDescriptor = this.conditionDescriptors[type];
+            operator = conditionDescriptor.defaultOperator;
+            ({value} = this.getOperatorDefaultValue(type, operator));
+            if (typeof value === 'undefined') {
+                value = '';
+            }
+        }
+        return {type, operator, value};
+    }
+
+    getOperatorDefaultValue(type, operator) {
+        if (this.conditionDescriptors.hasOwnProperty(type)) {
+            const conditionDescriptor = this.conditionDescriptors[type];
+            if (conditionDescriptor.operators.hasOwnProperty(operator)) {
+                const operatorDescriptor = conditionDescriptor.operators[operator];
+                if (operatorDescriptor.hasOwnProperty('defaultValue')) {
+                    return {value: operatorDescriptor.defaultValue, fromOperator: true};
+                }
+            }
+            if (conditionDescriptor.hasOwnProperty('defaultValue')) {
+                return {value: conditionDescriptor.defaultValue, fromOperator: false};
+            }
+        }
+        return {fromOperator: false};
+    }
+};
+
+ConditionsUI.ConditionGroup = class ConditionGroup {
+    constructor(parent, conditionGroup) {
+        this.parent = parent;
+        this.children = [];
+        this.conditionGroup = conditionGroup;
+        this.container = $('<div>').addClass('condition-group').appendTo(parent.container);
+        this.options = ConditionsUI.instantiateTemplate('#condition-group-options-template').appendTo(parent.container);
+        this.separator = ConditionsUI.instantiateTemplate('#condition-group-separator-template').appendTo(parent.container);
+        this.addButton = this.options.find('.condition-add');
+
+        for (const condition of conditionGroup.conditions) {
+            this.children.push(new ConditionsUI.Condition(this, condition));
+        }
+
+        this.addButton.on('click', () => this.onAddCondition());
+    }
+
+    cleanup() {
+        for (const child of this.children) {
+            child.cleanup();
+        }
+
+        this.addButton.off('click');
+        this.container.remove();
+        this.options.remove();
+        this.separator.remove();
+    }
+
+    save() {
+        this.parent.save();
+    }
+
+    isolate(object) {
+        return this.parent.isolate(object);
+    }
+
+    remove(child) {
+        const index = this.children.indexOf(child);
+        if (index < 0) {
+            return;
+        }
+
+        child.cleanup();
+        this.children.splice(index, 1);
+        this.conditionGroup.conditions.splice(index, 1);
+
+        if (this.children.length === 0) {
+            this.parent.remove(this, false);
+        }
+    }
+
+    onAddCondition() {
+        const condition = this.isolate(this.parent.createDefaultCondition(this.parent.conditionNameDefault));
+        this.conditionGroup.conditions.push(condition);
+        this.children.push(new ConditionsUI.Condition(this, condition));
+    }
+};
+
+ConditionsUI.Condition = class Condition {
+    constructor(parent, condition) {
+        this.parent = parent;
+        this.condition = condition;
+        this.container = ConditionsUI.instantiateTemplate('#condition-template').appendTo(parent.container);
+        this.input = this.container.find('input');
+        this.typeSelect = this.container.find('.condition-type');
+        this.operatorSelect = this.container.find('.condition-operator');
+        this.removeButton = this.container.find('.condition-remove');
+
+        this.updateTypes();
+        this.updateOperators();
+        this.updateInput();
+
+        this.input.on('change', () => this.onInputChanged());
+        this.typeSelect.on('change', () => this.onConditionTypeChanged());
+        this.operatorSelect.on('change', () => this.onConditionOperatorChanged());
+        this.removeButton.on('click', () => this.onRemoveClicked());
+    }
+
+    cleanup() {
+        this.input.off('change');
+        this.typeSelect.off('change');
+        this.operatorSelect.off('change');
+        this.removeButton.off('click');
+        this.container.remove();
+    }
+
+    save() {
+        this.parent.save();
+    }
+
+    updateTypes() {
+        const conditionDescriptors = this.parent.parent.conditionDescriptors;
+        const optionGroup = this.typeSelect.find('optgroup');
+        optionGroup.empty();
+        for (const type of Object.keys(conditionDescriptors)) {
+            const conditionDescriptor = conditionDescriptors[type];
+            $('<option>').val(type).text(conditionDescriptor.name).appendTo(optionGroup);
+        }
+        this.typeSelect.val(this.condition.type);
+    }
+
+    updateOperators() {
+        const conditionDescriptors = this.parent.parent.conditionDescriptors;
+        const optionGroup = this.operatorSelect.find('optgroup');
+        optionGroup.empty();
+
+        const type = this.condition.type;
+        if (conditionDescriptors.hasOwnProperty(type)) {
+            const conditionDescriptor = conditionDescriptors[type];
+            const operators = conditionDescriptor.operators;
+            for (const operatorName of Object.keys(operators)) {
+                const operatorDescriptor = operators[operatorName];
+                $('<option>').val(operatorName).text(operatorDescriptor.name).appendTo(optionGroup);
+            }
+        }
+
+        this.operatorSelect.val(this.condition.operator);
+    }
+
+    updateInput() {
+        const conditionDescriptors = this.parent.parent.conditionDescriptors;
+        const {type, operator} = this.condition;
+        const props = {
+            placeholder: '',
+            type: 'text'
+        };
+
+        const objects = [];
+        if (conditionDescriptors.hasOwnProperty(type)) {
+            const conditionDescriptor = conditionDescriptors[type];
+            objects.push(conditionDescriptor);
+            if (conditionDescriptor.operators.hasOwnProperty(operator)) {
+                const operatorDescriptor = conditionDescriptor.operators[operator];
+                objects.push(operatorDescriptor);
+            }
+        }
+
+        for (const object of objects) {
+            if (object.hasOwnProperty('placeholder')) {
+                props.placeholder = object.placeholder;
+            }
+            if (object.type === 'number') {
+                props.type = 'number';
+                for (const prop of ['step', 'min', 'max']) {
+                    if (object.hasOwnProperty(prop)) {
+                        props[prop] = object[prop];
+                    }
+                }
+            }
+        }
+
+        for (const prop in props) {
+            this.input.prop(prop, props[prop]);
+        }
+
+        const {valid} = this.validateValue(this.condition.value);
+        this.input.toggleClass('is-invalid', !valid);
+        this.input.val(this.condition.value);
+    }
+
+    validateValue(value) {
+        const conditionDescriptors = this.parent.parent.conditionDescriptors;
+        let valid = true;
+        try {
+            value = conditionsNormalizeOptionValue(
+                conditionDescriptors,
+                this.condition.type,
+                this.condition.operator,
+                value
+            );
+        } catch (e) {
+            valid = false;
+        }
+        return {valid, value};
+    }
+
+    onInputChanged() {
+        const {valid, value} = this.validateValue(this.input.val());
+        this.input.toggleClass('is-invalid', !valid);
+        this.input.val(value);
+        this.condition.value = value;
+        this.save();
+    }
+
+    onConditionTypeChanged() {
+        const type = this.typeSelect.val();
+        const {operator, value} = this.parent.parent.createDefaultCondition(type);
+        this.condition.type = type;
+        this.condition.operator = operator;
+        this.condition.value = value;
+        this.save();
+        this.updateOperators();
+        this.updateInput();
+    }
+
+    onConditionOperatorChanged() {
+        const type = this.condition.type;
+        const operator = this.operatorSelect.val();
+        const {value, fromOperator} = this.parent.parent.getOperatorDefaultValue(type, operator);
+        this.condition.operator = operator;
+        if (fromOperator) {
+            this.condition.value = value;
+        }
+        this.save();
+        this.updateInput();
+    }
+
+    onRemoveClicked() {
+        this.parent.remove(this);
+        this.save();
+    }
+};
diff --git a/ext/bg/js/conditions.js b/ext/bg/js/conditions.js
new file mode 100644
index 00000000..ed4b14f5
--- /dev/null
+++ b/ext/bg/js/conditions.js
@@ -0,0 +1,117 @@
+/*
+ * Copyright (C) 2019  Alex Yatskov <alex@foosoft.net>
+ * Author: Alex Yatskov <alex@foosoft.net>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+
+function conditionsValidateOptionValue(object, value) {
+    if (object.hasOwnProperty('validate') && !object.validate(value)) {
+        throw new Error('Invalid value for condition');
+    }
+
+    if (object.hasOwnProperty('transform')) {
+        value = object.transform(value);
+
+        if (object.hasOwnProperty('validateTransformed') && !object.validateTransformed(value)) {
+            throw new Error('Invalid value for condition');
+        }
+    }
+
+    return value;
+}
+
+function conditionsNormalizeOptionValue(descriptors, type, operator, optionValue) {
+    if (!descriptors.hasOwnProperty(type)) {
+        throw new Error('Invalid type');
+    }
+
+    const conditionDescriptor = descriptors[type];
+    if (!conditionDescriptor.operators.hasOwnProperty(operator)) {
+        throw new Error('Invalid operator');
+    }
+
+    const operatorDescriptor = conditionDescriptor.operators[operator];
+
+    let transformedValue = conditionsValidateOptionValue(conditionDescriptor, optionValue);
+    transformedValue = conditionsValidateOptionValue(operatorDescriptor, transformedValue);
+
+    if (operatorDescriptor.hasOwnProperty('transformReverse')) {
+        transformedValue = operatorDescriptor.transformReverse(transformedValue);
+    }
+    return transformedValue;
+}
+
+function conditionsTestValueThrowing(descriptors, type, operator, optionValue, value) {
+    if (!descriptors.hasOwnProperty(type)) {
+        throw new Error('Invalid type');
+    }
+
+    const conditionDescriptor = descriptors[type];
+    if (!conditionDescriptor.operators.hasOwnProperty(operator)) {
+        throw new Error('Invalid operator');
+    }
+
+    const operatorDescriptor = conditionDescriptor.operators[operator];
+    if (operatorDescriptor.hasOwnProperty('transform')) {
+        if (operatorDescriptor.hasOwnProperty('transformCache')) {
+            const key = `${optionValue}`;
+            const transformCache = operatorDescriptor.transformCache;
+            if (transformCache.hasOwnProperty(key)) {
+                optionValue = transformCache[key];
+            } else {
+                optionValue = operatorDescriptor.transform(optionValue);
+                transformCache[key] = optionValue;
+            }
+        } else {
+            optionValue = operatorDescriptor.transform(optionValue);
+        }
+    }
+
+    return operatorDescriptor.test(value, optionValue);
+}
+
+function conditionsTestValue(descriptors, type, operator, optionValue, value) {
+    try {
+        return conditionsTestValueThrowing(descriptors, type, operator, optionValue, value);
+    } catch (e) {
+        return false;
+    }
+}
+
+function conditionsClearCaches(descriptors) {
+    for (const type in descriptors) {
+        if (!descriptors.hasOwnProperty(type)) {
+            continue;
+        }
+
+        const conditionDescriptor = descriptors[type];
+        if (conditionDescriptor.hasOwnProperty('transformCache')) {
+            conditionDescriptor.transformCache = {};
+        }
+
+        const operatorDescriptors = conditionDescriptor.operators;
+        for (const operator in operatorDescriptors) {
+            if (!operatorDescriptors.hasOwnProperty(operator)) {
+                continue;
+            }
+
+            const operatorDescriptor = operatorDescriptors[operator];
+            if (operatorDescriptor.hasOwnProperty('transformCache')) {
+                operatorDescriptor.transformCache = {};
+            }
+        }
+    }
+}
diff --git a/ext/bg/js/context.js b/ext/bg/js/context.js
index dfa224a7..0f88e9c0 100644
--- a/ext/bg/js/context.js
+++ b/ext/bg/js/context.js
@@ -22,7 +22,10 @@ $(document).ready(utilAsync(() => {
     $('#open-options').click(() => apiCommandExec('options'));
     $('#open-help').click(() => apiCommandExec('help'));
 
-    const optionsContext = {depth: 0};
+    const optionsContext = {
+        depth: 0,
+        url: window.location.href
+    };
     apiOptionsGet(optionsContext).then(options => {
         const toggle = $('#enable-search');
         toggle.prop('checked', options.general.enable).change();
diff --git a/ext/bg/js/options.js b/ext/bg/js/options.js
index 3dce5221..e9e321df 100644
--- a/ext/bg/js/options.js
+++ b/ext/bg/js/options.js
@@ -329,6 +329,22 @@ function profileOptionsUpdateVersion(options) {
 
 /*
  * Global options
+ *
+ * Each profile has an array named "conditionGroups", which is an array of condition groups
+ * which enable the contextual selection of profiles. The structure of the array is as follows:
+ * [
+ *     {
+ *         conditions: [
+ *             {
+ *                 type: "string",
+ *                 operator: "string",
+ *                 value: "string"
+ *             },
+ *             // ...
+ *         ]
+ *     },
+ *     // ...
+ * ]
  */
 
 const optionsVersionUpdates = [];
@@ -351,7 +367,8 @@ function optionsUpdateVersion(options, defaultProfileOptions) {
     if (profiles.length === 0) {
         profiles.push({
             name: 'Default',
-            options: defaultProfileOptions
+            options: defaultProfileOptions,
+            conditionGroups: []
         });
     }
 
@@ -369,6 +386,9 @@ function optionsUpdateVersion(options, defaultProfileOptions) {
 
     // Update profile options
     for (const profile of profiles) {
+        if (!Array.isArray(profile.conditionGroups)) {
+            profile.conditionGroups = [];
+        }
         profile.options = profileOptionsUpdateVersion(profile.options);
     }
 
diff --git a/ext/bg/js/profile-conditions.js b/ext/bg/js/profile-conditions.js
new file mode 100644
index 00000000..5daa904e
--- /dev/null
+++ b/ext/bg/js/profile-conditions.js
@@ -0,0 +1,85 @@
+/*
+ * Copyright (C) 2019  Alex Yatskov <alex@foosoft.net>
+ * Author: Alex Yatskov <alex@foosoft.net>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+
+const profileConditionsDescriptor = {
+    popupLevel: {
+        name: 'Popup Level',
+        description: 'Use profile depending on the level of the popup.',
+        placeholder: 'Number',
+        type: 'number',
+        step: 1,
+        defaultValue: 0,
+        defaultOperator: 'equal',
+        transform: (optionValue) => parseInt(optionValue, 10),
+        transformReverse: (transformedOptionValue) => `${transformedOptionValue}`,
+        validateTransformed: (transformedOptionValue) => Number.isFinite(transformedOptionValue),
+        operators: {
+            equal: {
+                name: '=',
+                test: ({depth}, optionValue) => (depth === optionValue)
+            },
+            notEqual: {
+                name: '\u2260',
+                test: ({depth}, optionValue) => (depth !== optionValue)
+            },
+            lessThan: {
+                name: '<',
+                test: ({depth}, optionValue) => (depth < optionValue)
+            },
+            greaterThan: {
+                name: '>',
+                test: ({depth}, optionValue) => (depth > optionValue)
+            },
+            lessThanOrEqual: {
+                name: '\u2264',
+                test: ({depth}, optionValue) => (depth <= optionValue)
+            },
+            greaterThanOrEqual: {
+                name: '\u2265',
+                test: ({depth}, optionValue) => (depth >= optionValue)
+            }
+        }
+    },
+    url: {
+        name: 'URL',
+        description: 'Use profile depending on the URL of the current website.',
+        defaultOperator: 'matchDomain',
+        operators: {
+            matchDomain: {
+                name: 'Matches Domain',
+                placeholder: 'Comma separated list of domains',
+                defaultValue: 'example.com',
+                transformCache: {},
+                transform: (optionValue) => optionValue.split(/[,;\s]+/).map(v => v.trim().toLowerCase()).filter(v => v.length > 0),
+                transformReverse: (transformedOptionValue) => transformedOptionValue.join(', '),
+                validateTransformed: (transformedOptionValue) => (transformedOptionValue.length > 0),
+                test: ({url}, transformedOptionValue) => (transformedOptionValue.indexOf(new URL(url).hostname.toLowerCase()) >= 0)
+            },
+            matchRegExp: {
+                name: 'Matches RegExp',
+                placeholder: 'Regular expression',
+                defaultValue: 'example\\.com',
+                transformCache: {},
+                transform: (optionValue) => new RegExp(optionValue, 'i'),
+                transformReverse: (transformedOptionValue) => transformedOptionValue.source,
+                test: ({url}, transformedOptionValue) => (transformedOptionValue !== null && transformedOptionValue.test(url))
+            }
+        }
+    }
+};
diff --git a/ext/bg/js/search-frontend.js b/ext/bg/js/search-frontend.js
index df5ccf81..faec29ef 100644
--- a/ext/bg/js/search-frontend.js
+++ b/ext/bg/js/search-frontend.js
@@ -18,7 +18,10 @@
 
 
 async function searchFrontendSetup() {
-    const optionsContext = {depth: 0};
+    const optionsContext = {
+        depth: 0,
+        url: window.location.href
+    };
     const options = await apiOptionsGet(optionsContext);
     if (!options.scanning.enableOnSearchPage) { return; }
 
diff --git a/ext/bg/js/search.js b/ext/bg/js/search.js
index 6bdc47d8..6ff710f0 100644
--- a/ext/bg/js/search.js
+++ b/ext/bg/js/search.js
@@ -22,7 +22,8 @@ class DisplaySearch extends Display {
         super($('#spinner'), $('#content'));
 
         this.optionsContext = {
-            depth: 0
+            depth: 0,
+            url: window.location.href
         };
 
         this.search = $('#search').click(this.onSearch.bind(this));
diff --git a/ext/bg/js/settings-profiles.js b/ext/bg/js/settings-profiles.js
index 624562c6..ededc998 100644
--- a/ext/bg/js/settings-profiles.js
+++ b/ext/bg/js/settings-profiles.js
@@ -17,6 +17,7 @@
  */
 
 let currentProfileIndex = 0;
+let profileConditionsContainer = null;
 
 function getOptionsContext() {
     return {
@@ -81,6 +82,23 @@ async function profileFormWrite(optionsFull) {
     $('#profile-move-down').prop('disabled', currentProfileIndex >= optionsFull.profiles.length - 1);
 
     $('#profile-name').val(profile.name);
+
+    if (profileConditionsContainer !== null) {
+        profileConditionsContainer.cleanup();
+    }
+
+    profileConditionsContainer = new ConditionsUI.Container(
+        profileConditionsDescriptor,
+        'popupLevel',
+        profile.conditionGroups,
+        $('#profile-condition-groups'),
+        $('#profile-add-condition-group')
+    );
+    profileConditionsContainer.save = () => {
+        apiOptionsSave();
+        conditionsClearCaches(profileConditionsDescriptor);
+    };
+    profileConditionsContainer.isolate = utilBackgroundIsolate;
 }
 
 function profileOptionsPopulateSelect(select, profiles, currentValue, ignoreIndices) {
diff --git a/ext/bg/settings.html b/ext/bg/settings.html
index c0489894..d38aa090 100644
--- a/ext/bg/settings.html
+++ b/ext/bg/settings.html
@@ -34,6 +34,55 @@
                 font-weight: normal;
             }
 
+            .form-control.is-invalid {
+                border-color: #f00000;
+            }
+
+            .condition>.condition-prefix:after {
+                content: "IF";
+            }
+            .condition:nth-child(n+2)>.condition-prefix:after {
+                content: "AND";
+            }
+
+            .input-group .condition-prefix,
+            .input-group .condition-group-separator-label {
+                width: 60px;
+                text-align: center;
+            }
+            .input-group .condition-group-separator-label {
+                padding: 6px 12px;
+                font-weight: bold;
+                display: inline-block;
+            }
+            .input-group .condition-type,
+            .input-group .condition-operator {
+                width: auto;
+                text-align: center;
+                text-align-last: center;
+            }
+
+            .condition-group>.condition>div:first-child {
+                border-bottom-left-radius: 0;
+            }
+            .condition-group>.condition:nth-child(n+2)>div:first-child {
+                border-top-left-radius: 0;
+            }
+            .condition-group>.condition:nth-child(n+2)>div:last-child>button {
+                border-top-right-radius: 0;
+            }
+            .condition-group>.condition:nth-last-child(n+2)>div:last-child>button {
+                border-bottom-right-radius: 0;
+            }
+            .condition-group-options>.condition-add {
+                border-top-left-radius: 0;
+                border-top-right-radius: 0;
+            }
+
+            .condition-groups>*:last-of-type {
+                display: none;
+            }
+
             #custom-popup-css {
                 width: 100%;
                 min-height: 34px;
@@ -71,7 +120,7 @@
                 <h3>Profiles</h3>
 
                 <p class="help-block">
-                    Profiles allow you to create multiple configurations and quickly switch between them.
+                    Profiles allow you to create multiple configurations and quickly switch between them or use them in different contexts.
                 </p>
 
                 <div class="form-group">
@@ -100,6 +149,27 @@
                     <input type="text" id="profile-name" class="form-control">
                 </div>
 
+                <div class="form-group">
+                    <label>Usage conditions</label>
+
+                    <p class="help-block">
+                        Usage conditions can be assigned such that certain profiles are automatically used in different contexts.
+                        For example, when <a href="#popup-content-scanning">Popup Content Scanning</a> is enabled, different profiles can be used
+                        depending on the level of the popup.
+                    </p>
+
+                    <p class="help-block">
+                        Conditions are organized into groups which represent how the conditions are checked.
+                        If all of the conditions in any group are met, then the profile will automatically be used for that context.
+                        If no conditions are specified, the profile will only be used if it is selected as the <strong>Active profile</strong>.
+                    </p>
+
+                    <div class="condition-groups" id="profile-condition-groups"></div>
+                </div>
+                <div class="form-group">
+                    <button class="btn btn-default" id="profile-add-condition-group">Add Condition Group</button>
+                </div>
+
                 <div class="modal fade" tabindex="-1" role="dialog" id="profile-copy-modal">
                     <div class="modal-dialog modal-dialog-centered">
                         <div class="modal-content">
@@ -136,6 +206,20 @@
                         </div>
                     </div>
                 </div>
+
+                <template id="condition-template"><div class="input-group condition">
+                    <div class="input-group-addon condition-prefix"></div>
+                    <div class="input-group-btn"><select class="form-control btn btn-default condition-type"><optgroup label="Type"></optgroup></select></div>
+                    <div class="input-group-btn"><select class="form-control btn btn-default condition-operator"><optgroup label="Operator"></optgroup></select></div>
+                    <input type="text" class="form-control" />
+                    <div class="input-group-btn"><button class="btn btn-danger condition-remove" title="Remove"><span class="glyphicon glyphicon-remove"></span></button></div>
+                </div></template>
+                <template id="condition-group-separator-template"><div class="input-group">
+                    <div class="condition-group-separator-label">OR</div>
+                </div></template>
+                <template id="condition-group-options-template"><div class="condition-group-options">
+                    <button class="btn btn-default condition-add"><span class="glyphicon glyphicon-plus"></span></button>
+                </div></template>
             </div>
 
             <div>
@@ -563,9 +647,12 @@
 
         <script src="/bg/js/anki.js"></script>
         <script src="/bg/js/api.js"></script>
+        <script src="/bg/js/conditions.js"></script>
+        <script src="/bg/js/conditions-ui.js"></script>
         <script src="/bg/js/dictionary.js"></script>
         <script src="/bg/js/handlebars.js"></script>
         <script src="/bg/js/options.js"></script>
+        <script src="/bg/js/profile-conditions.js"></script>
         <script src="/bg/js/templates.js"></script>
         <script src="/bg/js/util.js"></script>
 
diff --git a/ext/fg/js/float.js b/ext/fg/js/float.js
index 348c114e..fd7986b8 100644
--- a/ext/fg/js/float.js
+++ b/ext/fg/js/float.js
@@ -24,7 +24,8 @@ class DisplayFloat extends Display {
         this.styleNode = null;
 
         this.optionsContext = {
-            depth: 0
+            depth: 0,
+            url: window.location.href
         };
 
         this.dependencies = Object.assign({}, this.dependencies, {docRangeFromPoint, docSentenceExtract});
@@ -78,9 +79,10 @@ class DisplayFloat extends Display {
                 }
             },
 
-            popupNestedInitialize: ({id, depth, parentFrameId}) => {
+            popupNestedInitialize: ({id, depth, parentFrameId, url}) => {
                 this.optionsContext.depth = depth;
-                popupNestedInitialize(id, depth, parentFrameId);
+                this.optionsContext.url = url;
+                popupNestedInitialize(id, depth, parentFrameId, url);
             }
         };
 
diff --git a/ext/fg/js/frontend.js b/ext/fg/js/frontend.js
index 564df343..167e82c0 100644
--- a/ext/fg/js/frontend.js
+++ b/ext/fg/js/frontend.js
@@ -27,7 +27,8 @@ class Frontend {
         this.ignoreNodes = (Array.isArray(ignoreNodes) && ignoreNodes.length > 0 ? ignoreNodes.join(',') : null);
 
         this.optionsContext = {
-            depth: popup.depth
+            depth: popup.depth,
+            url: popup.url
         };
 
         this.primaryTouchIdentifier = null;
@@ -42,9 +43,9 @@ class Frontend {
     static create() {
         const initializationData = window.frontendInitializationData;
         const isNested = (initializationData !== null && typeof initializationData === 'object');
-        const {id, depth, parentFrameId, ignoreNodes} = isNested ? initializationData : {};
+        const {id, depth, parentFrameId, ignoreNodes, url} = isNested ? initializationData : {};
 
-        const popup = isNested ? new PopupProxy(depth + 1, id, parentFrameId) : PopupProxyHost.instance.createPopup(null);
+        const popup = isNested ? new PopupProxy(depth + 1, id, parentFrameId, url) : PopupProxyHost.instance.createPopup(null);
         const frontend = new Frontend(popup, ignoreNodes);
         frontend.prepare();
         return frontend;
@@ -52,7 +53,7 @@ class Frontend {
 
     async prepare() {
         try {
-            this.options = await apiOptionsGet(this.optionsContext);
+            this.options = await apiOptionsGet(this.getOptionsContext());
 
             window.addEventListener('message', this.onFrameMessage.bind(this));
             window.addEventListener('mousedown', this.onMouseDown.bind(this));
@@ -262,7 +263,7 @@ class Frontend {
     }
 
     async updateOptions() {
-        this.options = await apiOptionsGet(this.optionsContext);
+        this.options = await apiOptionsGet(this.getOptionsContext());
         if (!this.options.enable) {
             this.searchClear();
         }
@@ -335,7 +336,7 @@ class Frontend {
             return;
         }
 
-        const {definitions, length} = await apiTermsFind(searchText, this.optionsContext);
+        const {definitions, length} = await apiTermsFind(searchText, this.getOptionsContext());
         if (definitions.length === 0) {
             return false;
         }
@@ -368,7 +369,7 @@ class Frontend {
             return;
         }
 
-        const definitions = await apiKanjiFind(searchText, this.optionsContext);
+        const definitions = await apiKanjiFind(searchText, this.getOptionsContext());
         if (definitions.length === 0) {
             return false;
         }
@@ -512,6 +513,11 @@ class Frontend {
         }
     }
 
+    getOptionsContext() {
+        this.optionsContext.url = this.popup.url;
+        return this.optionsContext;
+    }
+
     static isScanningModifierPressed(scanningModifier, mouseEvent) {
         switch (scanningModifier) {
             case 'alt': return mouseEvent.altKey;
diff --git a/ext/fg/js/popup-nested.js b/ext/fg/js/popup-nested.js
index de2acccc..b36de2ec 100644
--- a/ext/fg/js/popup-nested.js
+++ b/ext/fg/js/popup-nested.js
@@ -19,13 +19,13 @@
 
 let popupNestedInitialized = false;
 
-async function popupNestedInitialize(id, depth, parentFrameId) {
+async function popupNestedInitialize(id, depth, parentFrameId, url) {
     if (popupNestedInitialized) {
         return;
     }
     popupNestedInitialized = true;
 
-    const optionsContext = {depth};
+    const optionsContext = {depth, url};
     const options = await apiOptionsGet(optionsContext);
     const popupNestingMaxDepth = options.scanning.popupNestingMaxDepth;
 
@@ -35,7 +35,7 @@ async function popupNestedInitialize(id, depth, parentFrameId) {
 
     const ignoreNodes = options.scanning.enableOnPopupExpressions ? [] : [ '.expression', '.expression *' ];
 
-    window.frontendInitializationData = {id, depth, parentFrameId, ignoreNodes};
+    window.frontendInitializationData = {id, depth, parentFrameId, ignoreNodes, url};
 
     const scriptSrcs = [
         '/fg/js/frontend-api-sender.js',
diff --git a/ext/fg/js/popup-proxy.js b/ext/fg/js/popup-proxy.js
index f04e24e0..235e1730 100644
--- a/ext/fg/js/popup-proxy.js
+++ b/ext/fg/js/popup-proxy.js
@@ -18,7 +18,7 @@
 
 
 class PopupProxy {
-    constructor(depth, parentId, parentFrameId) {
+    constructor(depth, parentId, parentFrameId, url) {
         this.parentId = parentId;
         this.parentFrameId = parentFrameId;
         this.id = null;
@@ -26,6 +26,7 @@ class PopupProxy {
         this.parent = null;
         this.child = null;
         this.depth = depth;
+        this.url = url;
 
         this.container = null;
 
diff --git a/ext/fg/js/popup.js b/ext/fg/js/popup.js
index 8953cf30..08965084 100644
--- a/ext/fg/js/popup.js
+++ b/ext/fg/js/popup.js
@@ -59,7 +59,8 @@ class Popup {
                 this.invokeApi('popupNestedInitialize', {
                     id: this.id,
                     depth: this.depth,
-                    parentFrameId
+                    parentFrameId,
+                    url: this.url
                 });
                 this.invokeApi('setOptions', {
                     general: {
@@ -311,4 +312,8 @@ class Popup {
             parent.appendChild(this.container);
         }
     }
+
+    get url() {
+        return window.location.href;
+    }
 }