ru-se.com

customize-preview.js (27960B)

---

 /*
  * Script run inside a Customizer preview frame.
  *
  * @output wp-includes/js/customize-preview.js
  */
 (function( exports, $ ){
 	var api = wp.customize,
 		debounce,
 		currentHistoryState = {};
 
 	/*
 	 * Capture the state that is passed into history.replaceState() and history.pushState()
 	 * and also which is returned in the popstate event so that when the changeset_uuid
 	 * gets updated when transitioning to a new changeset there the current state will
 	 * be supplied in the call to history.replaceState().
 	 */
 	( function( history ) {
 		var injectUrlWithState;
 
 		if ( ! history.replaceState ) {
 			return;
 		}
 
 		/**
 		 * Amend the supplied URL with the customized state.
 		 *
 		 * @since 4.7.0
 		 * @access private
 		 *
 		 * @param {string} url URL.
 		 * @return {string} URL with customized state.
 		 */
 		injectUrlWithState = function( url ) {
 			var urlParser, oldQueryParams, newQueryParams;
 			urlParser = document.createElement( 'a' );
 			urlParser.href = url;
 			oldQueryParams = api.utils.parseQueryString( location.search.substr( 1 ) );
 			newQueryParams = api.utils.parseQueryString( urlParser.search.substr( 1 ) );
 
 			newQueryParams.customize_changeset_uuid = oldQueryParams.customize_changeset_uuid;
 			if ( oldQueryParams.customize_autosaved ) {
 				newQueryParams.customize_autosaved = 'on';
 			}
 			if ( oldQueryParams.customize_theme ) {
 				newQueryParams.customize_theme = oldQueryParams.customize_theme;
 			}
 			if ( oldQueryParams.customize_messenger_channel ) {
 				newQueryParams.customize_messenger_channel = oldQueryParams.customize_messenger_channel;
 			}
 			urlParser.search = $.param( newQueryParams );
 			return urlParser.href;
 		};
 
 		history.replaceState = ( function( nativeReplaceState ) {
 			return function historyReplaceState( data, title, url ) {
 				currentHistoryState = data;
 				return nativeReplaceState.call( history, data, title, 'string' === typeof url && url.length > 0 ? injectUrlWithState( url ) : url );
 			};
 		} )( history.replaceState );
 
 		history.pushState = ( function( nativePushState ) {
 			return function historyPushState( data, title, url ) {
 				currentHistoryState = data;
 				return nativePushState.call( history, data, title, 'string' === typeof url && url.length > 0 ? injectUrlWithState( url ) : url );
 			};
 		} )( history.pushState );
 
 		window.addEventListener( 'popstate', function( event ) {
 			currentHistoryState = event.state;
 		} );
 
 	}( history ) );
 
 	/**
 	 * Returns a debounced version of the function.
 	 *
 	 * @todo Require Underscore.js for this file and retire this.
 	 */
 	debounce = function( fn, delay, context ) {
 		var timeout;
 		return function() {
 			var args = arguments;
 
 			context = context || this;
 
 			clearTimeout( timeout );
 			timeout = setTimeout( function() {
 				timeout = null;
 				fn.apply( context, args );
 			}, delay );
 		};
 	};
 
 	/**
 	 * @memberOf wp.customize
 	 * @alias wp.customize.Preview
 	 *
 	 * @constructor
 	 * @augments wp.customize.Messenger
 	 * @augments wp.customize.Class
 	 * @mixes wp.customize.Events
 	 */
 	api.Preview = api.Messenger.extend(/** @lends wp.customize.Preview.prototype */{
 		/**
 		 * @param {Object} params  - Parameters to configure the messenger.
 		 * @param {Object} options - Extend any instance parameter or method with this object.
 		 */
 		initialize: function( params, options ) {
 			var preview = this, urlParser = document.createElement( 'a' );
 
 			api.Messenger.prototype.initialize.call( preview, params, options );
 
 			urlParser.href = preview.origin();
 			preview.add( 'scheme', urlParser.protocol.replace( /:$/, '' ) );
 
 			preview.body = $( document.body );
 			preview.window = $( window );
 
 			if ( api.settings.channel ) {
 
 				// If in an iframe, then intercept the link clicks and form submissions.
 				preview.body.on( 'click.preview', 'a', function( event ) {
 					preview.handleLinkClick( event );
 				} );
 				preview.body.on( 'submit.preview', 'form', function( event ) {
 					preview.handleFormSubmit( event );
 				} );
 
 				preview.window.on( 'scroll.preview', debounce( function() {
 					preview.send( 'scroll', preview.window.scrollTop() );
 				}, 200 ) );
 
 				preview.bind( 'scroll', function( distance ) {
 					preview.window.scrollTop( distance );
 				});
 			}
 		},
 
 		/**
 		 * Handle link clicks in preview.
 		 *
 		 * @since 4.7.0
 		 * @access public
 		 *
 		 * @param {jQuery.Event} event Event.
 		 */
 		handleLinkClick: function( event ) {
 			var preview = this, link, isInternalJumpLink;
 			link = $( event.target ).closest( 'a' );
 
 			// No-op if the anchor is not a link.
 			if ( _.isUndefined( link.attr( 'href' ) ) ) {
 				return;
 			}
 
 			// Allow internal jump links and JS links to behave normally without preventing default.
 			isInternalJumpLink = ( '#' === link.attr( 'href' ).substr( 0, 1 ) );
 			if ( isInternalJumpLink || ! /^https?:$/.test( link.prop( 'protocol' ) ) ) {
 				return;
 			}
 
 			// If the link is not previewable, prevent the browser from navigating to it.
 			if ( ! api.isLinkPreviewable( link[0] ) ) {
 				wp.a11y.speak( api.settings.l10n.linkUnpreviewable );
 				event.preventDefault();
 				return;
 			}
 
 			// Prevent initiating navigating from click and instead rely on sending url message to pane.
 			event.preventDefault();
 
 			/*
 			 * Note the shift key is checked so shift+click on widgets or
 			 * nav menu items can just result on focusing on the corresponding
 			 * control instead of also navigating to the URL linked to.
 			 */
 			if ( event.shiftKey ) {
 				return;
 			}
 
 			// Note: It's not relevant to send scroll because sending url message will have the same effect.
 			preview.send( 'url', link.prop( 'href' ) );
 		},
 
 		/**
 		 * Handle form submit.
 		 *
 		 * @since 4.7.0
 		 * @access public
 		 *
 		 * @param {jQuery.Event} event Event.
 		 */
 		handleFormSubmit: function( event ) {
 			var preview = this, urlParser, form;
 			urlParser = document.createElement( 'a' );
 			form = $( event.target );
 			urlParser.href = form.prop( 'action' );
 
 			// If the link is not previewable, prevent the browser from navigating to it.
 			if ( 'GET' !== form.prop( 'method' ).toUpperCase() || ! api.isLinkPreviewable( urlParser ) ) {
 				wp.a11y.speak( api.settings.l10n.formUnpreviewable );
 				event.preventDefault();
 				return;
 			}
 
 			/*
 			 * If the default wasn't prevented already (in which case the form
 			 * submission is already being handled by JS), and if it has a GET
 			 * request method, then take the serialized form data and add it as
 			 * a query string to the action URL and send this in a url message
 			 * to the customizer pane so that it will be loaded. If the form's
 			 * action points to a non-previewable URL, the customizer pane's
 			 * previewUrl setter will reject it so that the form submission is
 			 * a no-op, which is the same behavior as when clicking a link to an
 			 * external site in the preview.
 			 */
 			if ( ! event.isDefaultPrevented() ) {
 				if ( urlParser.search.length > 1 ) {
 					urlParser.search += '&';
 				}
 				urlParser.search += form.serialize();
 				preview.send( 'url', urlParser.href );
 			}
 
 			// Prevent default since navigation should be done via sending url message or via JS submit handler.
 			event.preventDefault();
 		}
 	});
 
 	/**
 	 * Inject the changeset UUID into links in the document.
 	 *
 	 * @since 4.7.0
 	 * @access protected
 	 * @access private
 	 *
 	 * @return {void}
 	 */
 	api.addLinkPreviewing = function addLinkPreviewing() {
 		var linkSelectors = 'a[href], area[href]';
 
 		// Inject links into initial document.
 		$( document.body ).find( linkSelectors ).each( function() {
 			api.prepareLinkPreview( this );
 		} );
 
 		// Inject links for new elements added to the page.
 		if ( 'undefined' !== typeof MutationObserver ) {
 			api.mutationObserver = new MutationObserver( function( mutations ) {
 				_.each( mutations, function( mutation ) {
 					$( mutation.target ).find( linkSelectors ).each( function() {
 						api.prepareLinkPreview( this );
 					} );
 				} );
 			} );
 			api.mutationObserver.observe( document.documentElement, {
 				childList: true,
 				subtree: true
 			} );
 		} else {
 
 			// If mutation observers aren't available, fallback to just-in-time injection.
 			$( document.documentElement ).on( 'click focus mouseover', linkSelectors, function() {
 				api.prepareLinkPreview( this );
 			} );
 		}
 	};
 
 	/**
 	 * Should the supplied link is previewable.
 	 *
 	 * @since 4.7.0
 	 * @access public
 	 *
 	 * @param {HTMLAnchorElement|HTMLAreaElement} element Link element.
 	 * @param {string} element.search Query string.
 	 * @param {string} element.pathname Path.
 	 * @param {string} element.host Host.
 	 * @param {Object} [options]
 	 * @param {Object} [options.allowAdminAjax=false] Allow admin-ajax.php requests.
 	 * @return {boolean} Is appropriate for changeset link.
 	 */
 	api.isLinkPreviewable = function isLinkPreviewable( element, options ) {
 		var matchesAllowedUrl, parsedAllowedUrl, args, elementHost;
 
 		args = _.extend( {}, { allowAdminAjax: false }, options || {} );
 
 		if ( 'javascript:' === element.protocol ) { // jshint ignore:line
 			return true;
 		}
 
 		// Only web URLs can be previewed.
 		if ( 'https:' !== element.protocol && 'http:' !== element.protocol ) {
 			return false;
 		}
 
 		elementHost = element.host.replace( /:(80|443)$/, '' );
 		parsedAllowedUrl = document.createElement( 'a' );
 		matchesAllowedUrl = ! _.isUndefined( _.find( api.settings.url.allowed, function( allowedUrl ) {
 			parsedAllowedUrl.href = allowedUrl;
 			return parsedAllowedUrl.protocol === element.protocol && parsedAllowedUrl.host.replace( /:(80|443)$/, '' ) === elementHost && 0 === element.pathname.indexOf( parsedAllowedUrl.pathname.replace( /\/$/, '' ) );
 		} ) );
 		if ( ! matchesAllowedUrl ) {
 			return false;
 		}
 
 		// Skip wp login and signup pages.
 		if ( /\/wp-(login|signup)\.php$/.test( element.pathname ) ) {
 			return false;
 		}
 
 		// Allow links to admin ajax as faux frontend URLs.
 		if ( /\/wp-admin\/admin-ajax\.php$/.test( element.pathname ) ) {
 			return args.allowAdminAjax;
 		}
 
 		// Disallow links to admin, includes, and content.
 		if ( /\/wp-(admin|includes|content)(\/|$)/.test( element.pathname ) ) {
 			return false;
 		}
 
 		return true;
 	};
 
 	/**
 	 * Inject the customize_changeset_uuid query param into links on the frontend.
 	 *
 	 * @since 4.7.0
 	 * @access protected
 	 *
 	 * @param {HTMLAnchorElement|HTMLAreaElement} element Link element.
 	 * @param {string} element.search Query string.
 	 * @param {string} element.host Host.
 	 * @param {string} element.protocol Protocol.
 	 * @return {void}
 	 */
 	api.prepareLinkPreview = function prepareLinkPreview( element ) {
 		var queryParams, $element = $( element );
 
         // Skip elements with no href attribute. Check first to avoid more expensive checks down the road.
         if ( ! element.hasAttribute( 'href' ) ) {
             return;
         }
 
 		// Skip links in admin bar.
 		if ( $element.closest( '#wpadminbar' ).length ) {
 			return;
 		}
 
 		// Ignore links with href="#", href="#id", or non-HTTP protocols (e.g. javascript: and mailto:).
 		if ( '#' === $element.attr( 'href' ).substr( 0, 1 ) || ! /^https?:$/.test( element.protocol ) ) {
 			return;
 		}
 
 		// Make sure links in preview use HTTPS if parent frame uses HTTPS.
 		if ( api.settings.channel && 'https' === api.preview.scheme.get() && 'http:' === element.protocol && -1 !== api.settings.url.allowedHosts.indexOf( element.host ) ) {
 			element.protocol = 'https:';
 		}
 
 		// Ignore links with class wp-playlist-caption.
 		if ( $element.hasClass( 'wp-playlist-caption' ) ) {
 			return;
 		}
 
 		if ( ! api.isLinkPreviewable( element ) ) {
 
 			// Style link as unpreviewable only if previewing in iframe; if previewing on frontend, links will be allowed to work normally.
 			if ( api.settings.channel ) {
 				$element.addClass( 'customize-unpreviewable' );
 			}
 			return;
 		}
 		$element.removeClass( 'customize-unpreviewable' );
 
 		queryParams = api.utils.parseQueryString( element.search.substring( 1 ) );
 		queryParams.customize_changeset_uuid = api.settings.changeset.uuid;
 		if ( api.settings.changeset.autosaved ) {
 			queryParams.customize_autosaved = 'on';
 		}
 		if ( ! api.settings.theme.active ) {
 			queryParams.customize_theme = api.settings.theme.stylesheet;
 		}
 		if ( api.settings.channel ) {
 			queryParams.customize_messenger_channel = api.settings.channel;
 		}
 		element.search = $.param( queryParams );
 	};
 
 	/**
 	 * Inject the changeset UUID into Ajax requests.
 	 *
 	 * @since 4.7.0
 	 * @access protected
 	 *
 	 * @return {void}
 	 */
 	api.addRequestPreviewing = function addRequestPreviewing() {
 
 		/**
 		 * Rewrite Ajax requests to inject customizer state.
 		 *
 		 * @param {Object} options Options.
 		 * @param {string} options.type Type.
 		 * @param {string} options.url URL.
 		 * @param {Object} originalOptions Original options.
 		 * @param {XMLHttpRequest} xhr XHR.
 		 * @return {void}
 		 */
 		var prefilterAjax = function( options, originalOptions, xhr ) {
 			var urlParser, queryParams, requestMethod, dirtyValues = {};
 			urlParser = document.createElement( 'a' );
 			urlParser.href = options.url;
 
 			// Abort if the request is not for this site.
 			if ( ! api.isLinkPreviewable( urlParser, { allowAdminAjax: true } ) ) {
 				return;
 			}
 			queryParams = api.utils.parseQueryString( urlParser.search.substring( 1 ) );
 
 			// Note that _dirty flag will be cleared with changeset updates.
 			api.each( function( setting ) {
 				if ( setting._dirty ) {
 					dirtyValues[ setting.id ] = setting.get();
 				}
 			} );
 
 			if ( ! _.isEmpty( dirtyValues ) ) {
 				requestMethod = options.type.toUpperCase();
 
 				// Override underlying request method to ensure unsaved changes to changeset can be included (force Backbone.emulateHTTP).
 				if ( 'POST' !== requestMethod ) {
 					xhr.setRequestHeader( 'X-HTTP-Method-Override', requestMethod );
 					queryParams._method = requestMethod;
 					options.type = 'POST';
 				}
 
 				// Amend the post data with the customized values.
 				if ( options.data ) {
 					options.data += '&';
 				} else {
 					options.data = '';
 				}
 				options.data += $.param( {
 					customized: JSON.stringify( dirtyValues )
 				} );
 			}
 
 			// Include customized state query params in URL.
 			queryParams.customize_changeset_uuid = api.settings.changeset.uuid;
 			if ( api.settings.changeset.autosaved ) {
 				queryParams.customize_autosaved = 'on';
 			}
 			if ( ! api.settings.theme.active ) {
 				queryParams.customize_theme = api.settings.theme.stylesheet;
 			}
 
 			// Ensure preview nonce is included with every customized request, to allow post data to be read.
 			queryParams.customize_preview_nonce = api.settings.nonce.preview;
 
 			urlParser.search = $.param( queryParams );
 			options.url = urlParser.href;
 		};
 
 		$.ajaxPrefilter( prefilterAjax );
 	};
 
 	/**
 	 * Inject changeset UUID into forms, allowing preview to persist through submissions.
 	 *
 	 * @since 4.7.0
 	 * @access protected
 	 *
 	 * @return {void}
 	 */
 	api.addFormPreviewing = function addFormPreviewing() {
 
 		// Inject inputs for forms in initial document.
 		$( document.body ).find( 'form' ).each( function() {
 			api.prepareFormPreview( this );
 		} );
 
 		// Inject inputs for new forms added to the page.
 		if ( 'undefined' !== typeof MutationObserver ) {
 			api.mutationObserver = new MutationObserver( function( mutations ) {
 				_.each( mutations, function( mutation ) {
 					$( mutation.target ).find( 'form' ).each( function() {
 						api.prepareFormPreview( this );
 					} );
 				} );
 			} );
 			api.mutationObserver.observe( document.documentElement, {
 				childList: true,
 				subtree: true
 			} );
 		}
 	};
 
 	/**
 	 * Inject changeset into form inputs.
 	 *
 	 * @since 4.7.0
 	 * @access protected
 	 *
 	 * @param {HTMLFormElement} form Form.
 	 * @return {void}
 	 */
 	api.prepareFormPreview = function prepareFormPreview( form ) {
 		var urlParser, stateParams = {};
 
 		if ( ! form.action ) {
 			form.action = location.href;
 		}
 
 		urlParser = document.createElement( 'a' );
 		urlParser.href = form.action;
 
 		// Make sure forms in preview use HTTPS if parent frame uses HTTPS.
 		if ( api.settings.channel && 'https' === api.preview.scheme.get() && 'http:' === urlParser.protocol && -1 !== api.settings.url.allowedHosts.indexOf( urlParser.host ) ) {
 			urlParser.protocol = 'https:';
 			form.action = urlParser.href;
 		}
 
 		if ( 'GET' !== form.method.toUpperCase() || ! api.isLinkPreviewable( urlParser ) ) {
 
 			// Style form as unpreviewable only if previewing in iframe; if previewing on frontend, all forms will be allowed to work normally.
 			if ( api.settings.channel ) {
 				$( form ).addClass( 'customize-unpreviewable' );
 			}
 			return;
 		}
 		$( form ).removeClass( 'customize-unpreviewable' );
 
 		stateParams.customize_changeset_uuid = api.settings.changeset.uuid;
 		if ( api.settings.changeset.autosaved ) {
 			stateParams.customize_autosaved = 'on';
 		}
 		if ( ! api.settings.theme.active ) {
 			stateParams.customize_theme = api.settings.theme.stylesheet;
 		}
 		if ( api.settings.channel ) {
 			stateParams.customize_messenger_channel = api.settings.channel;
 		}
 
 		_.each( stateParams, function( value, name ) {
 			var input = $( form ).find( 'input[name="' + name + '"]' );
 			if ( input.length ) {
 				input.val( value );
 			} else {
 				$( form ).prepend( $( '<input>', {
 					type: 'hidden',
 					name: name,
 					value: value
 				} ) );
 			}
 		} );
 
 		// Prevent links from breaking out of preview iframe.
 		if ( api.settings.channel ) {
 			form.target = '_self';
 		}
 	};
 
 	/**
 	 * Watch current URL and send keep-alive (heartbeat) messages to the parent.
 	 *
 	 * Keep the customizer pane notified that the preview is still alive
 	 * and that the user hasn't navigated to a non-customized URL.
 	 *
 	 * @since 4.7.0
 	 * @access protected
 	 */
 	api.keepAliveCurrentUrl = ( function() {
 		var previousPathName = location.pathname,
 			previousQueryString = location.search.substr( 1 ),
 			previousQueryParams = null,
 			stateQueryParams = [ 'customize_theme', 'customize_changeset_uuid', 'customize_messenger_channel', 'customize_autosaved' ];
 
 		return function keepAliveCurrentUrl() {
 			var urlParser, currentQueryParams;
 
 			// Short-circuit with keep-alive if previous URL is identical (as is normal case).
 			if ( previousQueryString === location.search.substr( 1 ) && previousPathName === location.pathname ) {
 				api.preview.send( 'keep-alive' );
 				return;
 			}
 
 			urlParser = document.createElement( 'a' );
 			if ( null === previousQueryParams ) {
 				urlParser.search = previousQueryString;
 				previousQueryParams = api.utils.parseQueryString( previousQueryString );
 				_.each( stateQueryParams, function( name ) {
 					delete previousQueryParams[ name ];
 				} );
 			}
 
 			// Determine if current URL minus customized state params and URL hash.
 			urlParser.href = location.href;
 			currentQueryParams = api.utils.parseQueryString( urlParser.search.substr( 1 ) );
 			_.each( stateQueryParams, function( name ) {
 				delete currentQueryParams[ name ];
 			} );
 
 			if ( previousPathName !== location.pathname || ! _.isEqual( previousQueryParams, currentQueryParams ) ) {
 				urlParser.search = $.param( currentQueryParams );
 				urlParser.hash = '';
 				api.settings.url.self = urlParser.href;
 				api.preview.send( 'ready', {
 					currentUrl: api.settings.url.self,
 					activePanels: api.settings.activePanels,
 					activeSections: api.settings.activeSections,
 					activeControls: api.settings.activeControls,
 					settingValidities: api.settings.settingValidities
 				} );
 			} else {
 				api.preview.send( 'keep-alive' );
 			}
 			previousQueryParams = currentQueryParams;
 			previousQueryString = location.search.substr( 1 );
 			previousPathName = location.pathname;
 		};
 	} )();
 
 	api.settingPreviewHandlers = {
 
 		/**
 		 * Preview changes to custom logo.
 		 *
 		 * @param {number} attachmentId Attachment ID for custom logo.
 		 * @return {void}
 		 */
 		custom_logo: function( attachmentId ) {
 			$( 'body' ).toggleClass( 'wp-custom-logo', !! attachmentId );
 		},
 
 		/**
 		 * Preview changes to custom css.
 		 *
 		 * @param {string} value Custom CSS..
 		 * @return {void}
 		 */
 		custom_css: function( value ) {
 			$( '#wp-custom-css' ).text( value );
 		},
 
 		/**
 		 * Preview changes to any of the background settings.
 		 *
 		 * @return {void}
 		 */
 		background: function() {
 			var css = '', settings = {};
 
 			_.each( ['color', 'image', 'preset', 'position_x', 'position_y', 'size', 'repeat', 'attachment'], function( prop ) {
 				settings[ prop ] = api( 'background_' + prop );
 			} );
 
 			/*
 			 * The body will support custom backgrounds if either the color or image are set.
 			 *
 			 * See get_body_class() in /wp-includes/post-template.php
 			 */
 			$( document.body ).toggleClass( 'custom-background', !! ( settings.color() || settings.image() ) );
 
 			if ( settings.color() ) {
 				css += 'background-color: ' + settings.color() + ';';
 			}
 
 			if ( settings.image() ) {
 				css += 'background-image: url("' + settings.image() + '");';
 				css += 'background-size: ' + settings.size() + ';';
 				css += 'background-position: ' + settings.position_x() + ' ' + settings.position_y() + ';';
 				css += 'background-repeat: ' + settings.repeat() + ';';
 				css += 'background-attachment: ' + settings.attachment() + ';';
 			}
 
 			$( '#custom-background-css' ).text( 'body.custom-background { ' + css + ' }' );
 		}
 	};
 
 	$( function() {
 		var bg, setValue, handleUpdatedChangesetUuid;
 
 		api.settings = window._wpCustomizeSettings;
 		if ( ! api.settings ) {
 			return;
 		}
 
 		api.preview = new api.Preview({
 			url: window.location.href,
 			channel: api.settings.channel
 		});
 
 		api.addLinkPreviewing();
 		api.addRequestPreviewing();
 		api.addFormPreviewing();
 
 		/**
 		 * Create/update a setting value.
 		 *
 		 * @param {string}  id            - Setting ID.
 		 * @param {*}       value         - Setting value.
 		 * @param {boolean} [createDirty] - Whether to create a setting as dirty. Defaults to false.
 		 */
 		setValue = function( id, value, createDirty ) {
 			var setting = api( id );
 			if ( setting ) {
 				setting.set( value );
 			} else {
 				createDirty = createDirty || false;
 				setting = api.create( id, value, {
 					id: id
 				} );
 
 				// Mark dynamically-created settings as dirty so they will get posted.
 				if ( createDirty ) {
 					setting._dirty = true;
 				}
 			}
 		};
 
 		api.preview.bind( 'settings', function( values ) {
 			$.each( values, setValue );
 		});
 
 		api.preview.trigger( 'settings', api.settings.values );
 
 		$.each( api.settings._dirty, function( i, id ) {
 			var setting = api( id );
 			if ( setting ) {
 				setting._dirty = true;
 			}
 		} );
 
 		api.preview.bind( 'setting', function( args ) {
 			var createDirty = true;
 			setValue.apply( null, args.concat( createDirty ) );
 		});
 
 		api.preview.bind( 'sync', function( events ) {
 
 			/*
 			 * Delete any settings that already exist locally which haven't been
 			 * modified in the controls while the preview was loading. This prevents
 			 * situations where the JS value being synced from the pane may differ
 			 * from the PHP-sanitized JS value in the preview which causes the
 			 * non-sanitized JS value to clobber the PHP-sanitized value. This
 			 * is particularly important for selective refresh partials that
 			 * have a fallback refresh behavior since infinite refreshing would
 			 * result.
 			 */
 			if ( events.settings && events['settings-modified-while-loading'] ) {
 				_.each( _.keys( events.settings ), function( syncedSettingId ) {
 					if ( api.has( syncedSettingId ) && ! events['settings-modified-while-loading'][ syncedSettingId ] ) {
 						delete events.settings[ syncedSettingId ];
 					}
 				} );
 			}
 
 			$.each( events, function( event, args ) {
 				api.preview.trigger( event, args );
 			});
 			api.preview.send( 'synced' );
 		});
 
 		api.preview.bind( 'active', function() {
 			api.preview.send( 'nonce', api.settings.nonce );
 
 			api.preview.send( 'documentTitle', document.title );
 
 			// Send scroll in case of loading via non-refresh.
 			api.preview.send( 'scroll', $( window ).scrollTop() );
 		});
 
 		/**
 		 * Handle update to changeset UUID.
 		 *
 		 * @param {string} uuid - UUID.
 		 * @return {void}
 		 */
 		handleUpdatedChangesetUuid = function( uuid ) {
 			api.settings.changeset.uuid = uuid;
 
 			// Update UUIDs in links and forms.
 			$( document.body ).find( 'a[href], area[href]' ).each( function() {
 				api.prepareLinkPreview( this );
 			} );
 			$( document.body ).find( 'form' ).each( function() {
 				api.prepareFormPreview( this );
 			} );
 
 			/*
 			 * Replace the UUID in the URL. Note that the wrapped history.replaceState()
 			 * will handle injecting the current api.settings.changeset.uuid into the URL,
 			 * so this is merely to trigger that logic.
 			 */
 			if ( history.replaceState ) {
 				history.replaceState( currentHistoryState, '', location.href );
 			}
 		};
 
 		api.preview.bind( 'changeset-uuid', handleUpdatedChangesetUuid );
 
 		api.preview.bind( 'saved', function( response ) {
 			if ( response.next_changeset_uuid ) {
 				handleUpdatedChangesetUuid( response.next_changeset_uuid );
 			}
 			api.trigger( 'saved', response );
 		} );
 
 		// Update the URLs to reflect the fact we've started autosaving.
 		api.preview.bind( 'autosaving', function() {
 			if ( api.settings.changeset.autosaved ) {
 				return;
 			}
 
 			api.settings.changeset.autosaved = true; // Start deferring to any autosave once changeset is updated.
 
 			$( document.body ).find( 'a[href], area[href]' ).each( function() {
 				api.prepareLinkPreview( this );
 			} );
 			$( document.body ).find( 'form' ).each( function() {
 				api.prepareFormPreview( this );
 			} );
 			if ( history.replaceState ) {
 				history.replaceState( currentHistoryState, '', location.href );
 			}
 		} );
 
 		/*
 		 * Clear dirty flag for settings when saved to changeset so that they
 		 * won't be needlessly included in selective refresh or ajax requests.
 		 */
 		api.preview.bind( 'changeset-saved', function( data ) {
 			_.each( data.saved_changeset_values, function( value, settingId ) {
 				var setting = api( settingId );
 				if ( setting && _.isEqual( setting.get(), value ) ) {
 					setting._dirty = false;
 				}
 			} );
 		} );
 
 		api.preview.bind( 'nonce-refresh', function( nonce ) {
 			$.extend( api.settings.nonce, nonce );
 		} );
 
 		/*
 		 * Send a message to the parent customize frame with a list of which
 		 * containers and controls are active.
 		 */
 		api.preview.send( 'ready', {
 			currentUrl: api.settings.url.self,
 			activePanels: api.settings.activePanels,
 			activeSections: api.settings.activeSections,
 			activeControls: api.settings.activeControls,
 			settingValidities: api.settings.settingValidities
 		} );
 
 		// Send ready when URL changes via JS.
 		setInterval( api.keepAliveCurrentUrl, api.settings.timeouts.keepAliveSend );
 
 		// Display a loading indicator when preview is reloading, and remove on failure.
 		api.preview.bind( 'loading-initiated', function () {
 			$( 'body' ).addClass( 'wp-customizer-unloading' );
 		});
 		api.preview.bind( 'loading-failed', function () {
 			$( 'body' ).removeClass( 'wp-customizer-unloading' );
 		});
 
 		/* Custom Backgrounds */
 		bg = $.map( ['color', 'image', 'preset', 'position_x', 'position_y', 'size', 'repeat', 'attachment'], function( prop ) {
 			return 'background_' + prop;
 		} );
 
 		api.when.apply( api, bg ).done( function() {
 			$.each( arguments, function() {
 				this.bind( api.settingPreviewHandlers.background );
 			});
 		});
 
 		/**
 		 * Custom Logo
 		 *
 		 * Toggle the wp-custom-logo body class when a logo is added or removed.
 		 *
 		 * @since 4.5.0
 		 */
 		api( 'custom_logo', function ( setting ) {
 			api.settingPreviewHandlers.custom_logo.call( setting, setting.get() );
 			setting.bind( api.settingPreviewHandlers.custom_logo );
 		} );
 
 		api( 'custom_css[' + api.settings.theme.stylesheet + ']', function( setting ) {
 			setting.bind( api.settingPreviewHandlers.custom_css );
 		} );
 
 		api.trigger( 'preview-ready' );
 	});
 
 })( wp, jQuery );