respond.src.js 9.26 KB

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/*! matchMedia() polyfill - Test a CSS media type/query in JS. Authors & copyright (c) 2012: Scott Jehl, Paul Irish, Nicholas Zakas. Dual MIT/BSD license */
/*! NOTE: If you're already including a window.matchMedia polyfill via Modernizr or otherwise, you don't need this part */
window.matchMedia = window.matchMedia || (function(doc, undefined){

  var bool,
      docElem  = doc.documentElement,
      refNode  = docElem.firstElementChild || docElem.firstChild,
      // fakeBody required for <FF4 when executed in <head>
      fakeBody = doc.createElement('body'),
      div      = doc.createElement('div');

  div.id = 'mq-test-1';
  div.style.cssText = "position:absolute;top:-100em";
  fakeBody.style.background = "none";
  fakeBody.appendChild(div);

  return function(q){

    div.innerHTML = '&shy;<style media="'+q+'"> #mq-test-1 { width: 42px; }</style>';

    docElem.insertBefore(fakeBody, refNode);
    bool = div.offsetWidth == 42;
    docElem.removeChild(fakeBody);

    return { matches: bool, media: q };
  };

})(document);


/*! Respond.js v1.1.0: min/max-width media query polyfill. (c) Scott Jehl. MIT/GPLv2 Lic. j.mp/respondjs  */
(function( win ){
	// Exposed namespace
	win.respond = {};

	// Define update even in native-mq-supporting browsers, to avoid errors
	respond.update = function(){};

	// Expose media query support flag for external use
	respond.mediaQueriesSupported = win.matchMedia && win.matchMedia( "only all" ).matches;

	// If media queries are supported, exit here
	if ( respond.mediaQueriesSupported ){ return; }

	// Define vars
	var doc            = win.document,
		docElem        = doc.documentElement,
		mediastyles    = [],
		rules          = [],
		appendedEls    = [],
		parsedSheets   = {},
		resizeThrottle = 30,
		head           = doc.getElementsByTagName( "head" )[0] || docElem,
		base           = doc.getElementsByTagName( "base" )[0],
		links          = head.getElementsByTagName( "link" ),
		requestQueue   = [],

		// Loop stylesheets, send text content to translate
		ripCSS = function(){

			var sheets = links,
				sl     = sheets.length,
				i      = 0,
				// Vars for loop:
				sheet, href, media, isCSS;

			for( ; i < sl; i++ ){
				sheet = sheets[ i ],
				href  = sheet.href,
				media = sheet.media,
				isCSS = sheet.rel && sheet.rel.toLowerCase() === "stylesheet";

				//only links plz and prevent re-parsing
				if ( !!href && isCSS && !parsedSheets[ href ] ){
					// selectivizr exposes css through the rawCssText expando
					if (sheet.styleSheet && sheet.styleSheet.rawCssText) {
						translate( sheet.styleSheet.rawCssText, href, media );
						parsedSheets[ href ] = true;
					} else {

						if ( (!/^([a-zA-Z:]*\/\/)/.test( href ) && !base)
							|| href.replace( RegExp.$1, "" ).split( "/" )[0] === win.location.host ){
							requestQueue.push( {
								href: href,
								media: media
							} );
						}
					}
				}
			}
			makeRequests();
		},

		// Recurse through request queue, get css text
		makeRequests = function(){

			if ( requestQueue.length ){
				var thisRequest = requestQueue.shift();

				ajax( thisRequest.href, function( styles ){

					translate( styles, thisRequest.href, thisRequest.media );
					parsedSheets[ thisRequest.href ] = true;
					makeRequests();
				} );
			}
		},

		// Find media blocks in css text, convert to style blocks
		translate       = function( styles, href, media ){
			var qs      = styles.match(  /@media[^\{]+\{([^\{\}]*\{[^\}\{]*\})+/gi ),
				ql      = qs && qs.length || 0,
				// Try to get CSS path
				href    = href.substring( 0, href.lastIndexOf( "/" )),
				repUrls = function( css ){
					return css.replace( /(url\()['"]?([^\/\)'"][^:\)'"]+)['"]?(\))/g, "$1" + href + "$2$3" );
				},
				useMedia = !ql && media,
				// Vars used in loop
				i        = 0,
				j, fullq, thisq, eachq, eql;

			// If path exists, tack on trailing slash
			if ( href.length ){ href += "/"; }

			//if no internal queries exist, but media attr does, use that
			//note: this currently lacks support for situations where a media attr is specified on a link AND
				//its associated stylesheet has internal CSS media queries.
				//In those cases, the media attribute will currently be ignored.
			if ( useMedia ){
				ql = 1;
			}

			for( ; i < ql; i++ ){
				j = 0;

				// Media attr
				if ( useMedia ){
					fullq = media;
					rules.push( repUrls( styles ) );
				}
				// Parse for styles
				else{
					fullq = qs[ i ].match( /@media *([^\{]+)\{([\S\s]+?)$/ ) && RegExp.$1;
					rules.push( RegExp.$2 && repUrls( RegExp.$2 ) );
				}

				eachq = fullq.split( "," );
				eql   = eachq.length;

				for( ; j < eql; j++ ){
					thisq = eachq[ j ];
					mediastyles.push( {
						media    : thisq.split( "(" )[ 0 ].match( /(only\s+)?([a-zA-Z]+)\s?/ ) && RegExp.$2 || "all",
						rules    : rules.length - 1,
						hasquery : thisq.indexOf("(") > -1,
						minw     : thisq.match( /\(min\-width:[\s]*([\s]*[0-9\.]+)(px|em)[\s]*\)/ ) && parseFloat( RegExp.$1 ) + ( RegExp.$2 || "" ),
						maxw     : thisq.match( /\(max\-width:[\s]*([\s]*[0-9\.]+)(px|em)[\s]*\)/ ) && parseFloat( RegExp.$1 ) + ( RegExp.$2 || "" )
					} );
				}
			}

			applyMedia();
		},

		lastCall,

		resizeDefer,

		// returns the value of 1em in pixels
		getEmValue = function() {
			var ret,
				div      = doc.createElement('div'),
				body     = doc.body,
				fakeUsed = false;

			div.style.cssText = "position:absolute;font-size:1em;width:1em";

			if ( !body ){
				body = fakeUsed = doc.createElement( "body" );
				body.style.background = "none";
			}

			body.appendChild( div );

			docElem.insertBefore( body, docElem.firstChild );

			ret = div.offsetWidth;

			if ( fakeUsed ){
				docElem.removeChild( body );
			}
			else {
				body.removeChild( div );
			}

			// Also update eminpx before returning
			ret = eminpx = parseFloat(ret);

			return ret;
		},

		// Cached container for 1em value, populated the first time it's needed
		eminpx,

		// Enable/disable styles
		applyMedia          = function( fromResize ){
			var name        = "clientWidth",
				docElemProp = docElem[ name ],
				currWidth   = doc.compatMode === "CSS1Compat" && docElemProp || doc.body[ name ] || docElemProp,
				styleBlocks = {},
				lastLink    = links[ links.length-1 ],
				now         = (new Date()).getTime();

			// Throttle resize calls
			if ( fromResize && lastCall && now - lastCall < resizeThrottle ){
				clearTimeout( resizeDefer );
				resizeDefer = setTimeout( applyMedia, resizeThrottle );
				return;
			}
			else {
				lastCall = now;
			}

			for( var i in mediastyles ){
				var thisstyle = mediastyles[ i ],
					min = thisstyle.minw,
					max = thisstyle.maxw,
					minnull = min === null,
					maxnull = max === null,
					em = "em";

				if ( !!min ){
					min = parseFloat( min ) * ( min.indexOf( em ) > -1 ? ( eminpx || getEmValue() ) : 1 );
				}
				if ( !!max ){
					max = parseFloat( max ) * ( max.indexOf( em ) > -1 ? ( eminpx || getEmValue() ) : 1 );
				}

				// If there's no media query at all (the () part), or min or max is not null, and if either is present, they're true
				if ( !thisstyle.hasquery || ( !minnull || !maxnull ) && ( minnull || currWidth >= min ) && ( maxnull || currWidth <= max ) ){
						if ( !styleBlocks[ thisstyle.media ] ){
							styleBlocks[ thisstyle.media ] = [];
						}
						styleBlocks[ thisstyle.media ].push( rules[ thisstyle.rules ] );
				}
			}

			// Remove any existing respond style element(s)
			for( var i in appendedEls ){
				if ( appendedEls[ i ] && appendedEls[ i ].parentNode === head ){
					head.removeChild( appendedEls[ i ] );
				}
			}

			// Inject active styles, grouped by media type
			for( var i in styleBlocks ){
				var ss  = doc.createElement( "style" ),
					css = styleBlocks[ i ].join( "\n" );

				ss.type  = "text/css";
				ss.media = i;

				// Originally, ss was appended to a documentFragment and sheets were appended in bulk.
				// This caused crashes in IE in a number of circumstances, such as when the HTML element had a bg image set, so appending beforehand seems best. Thanks to @dvelyk for the initial research on this one!
				head.insertBefore( ss, lastLink.nextSibling );

				if ( ss.styleSheet ){
					ss.styleSheet.cssText = css;
				}
				else{
					ss.appendChild( doc.createTextNode( css ) );
		        }

				// Push to appendedEls to track for later removal
				appendedEls.push( ss );
			}
		},
		// Tweaked Ajax functions from Quirksmode
		ajax = function( url, callback ) {
			var req = xmlHttp();
			if (!req){
				return;
			}
			req.open( "GET", url, true );
			req.onreadystatechange = function () {
				if ( req.readyState != 4 || req.status != 200 && req.status != 304 ){
					return;
				}
				callback( req.responseText );
			}
			if ( req.readyState == 4 ){
				return;
			}
			req.send( null );
		},
		// Define ajax obj
		xmlHttp = (function() {
			var xmlhttpmethod = false;
			try {
				xmlhttpmethod = new XMLHttpRequest();
			}
			catch( e ){
				xmlhttpmethod = new ActiveXObject( "Microsoft.XMLHTTP" );
			}
			return function(){
				return xmlhttpmethod;
			};
		})();

	// Translate CSS
	ripCSS();

	// Expose update for re-running respond later on
	respond.update = ripCSS;

	// Adjust on resize
	function callMedia(){
		applyMedia( true );
	}
	if ( win.addEventListener ){
		win.addEventListener( "resize", callMedia, false );
	}
	else if( win.attachEvent ){
		win.attachEvent( "onresize", callMedia );
	}
})(this);