git.piffa.net Git - aerei_site/blob - js/respond.js

   1 /* Respond.js: min/max-width media query polyfill. (c) Scott Jehl. MIT Lic. j.mp/respondjs  */
   2 (function( w ){
   3
   4         "use strict";
   5
   6         //exposed namespace
   7         var respond = {};
   8         w.respond = respond;
   9
  10         //define update even in native-mq-supporting browsers, to avoid errors
  11         respond.update = function(){};
  12
  13         //define ajax obj
  14         var requestQueue = [],
  15                 xmlHttp = (function() {
  16                         var xmlhttpmethod = false;
  17                         try {
  18                                 xmlhttpmethod = new w.XMLHttpRequest();
  19                         }
  20                         catch( e ){
  21                                 xmlhttpmethod = new w.ActiveXObject( "Microsoft.XMLHTTP" );
  22                         }
  23                         return function(){
  24                                 return xmlhttpmethod;
  25                         };
  26                 })(),
  27
  28                 //tweaked Ajax functions from Quirksmode
  29                 ajax = function( url, callback ) {
  30                         var req = xmlHttp();
  31                         if (!req){
  32                                 return;
  33                         }
  34                         req.open( "GET", url, true );
  35                         req.onreadystatechange = function () {
  36                                 if ( req.readyState !== 4 || req.status !== 200 && req.status !== 304 ){
  37                                         return;
  38                                 }
  39                                 callback( req.responseText );
  40                         };
  41                         if ( req.readyState === 4 ){
  42                                 return;
  43                         }
  44                         req.send( null );
  45                 },
  46                 isUnsupportedMediaQuery = function( query ) {
  47                         return query.replace( respond.regex.minmaxwh, '' ).match( respond.regex.other );
  48                 };
  49
  50         //expose for testing
  51         respond.ajax = ajax;
  52         respond.queue = requestQueue;
  53         respond.unsupportedmq = isUnsupportedMediaQuery;
  54         respond.regex = {
  55                 media: /@media[^\{]+\{([^\{\}]*\{[^\}\{]*\})+/gi,
  56                 keyframes: /@(?:\-(?:o|moz|webkit)\-)?keyframes[^\{]+\{(?:[^\{\}]*\{[^\}\{]*\})+[^\}]*\}/gi,
  57                 comments: /\/\*[^*]*\*+([^/][^*]*\*+)*\//gi,
  58                 urls: /(url\()['"]?([^\/\)'"][^:\)'"]+)['"]?(\))/g,
  59                 findStyles: /@media *([^\{]+)\{([\S\s]+?)$/,
  60                 only: /(only\s+)?([a-zA-Z]+)\s?/,
  61                 minw: /\(\s*min\-width\s*:\s*(\s*[0-9\.]+)(px|em)\s*\)/,
  62                 maxw: /\(\s*max\-width\s*:\s*(\s*[0-9\.]+)(px|em)\s*\)/,
  63                 minmaxwh: /\(\s*m(in|ax)\-(height|width)\s*:\s*(\s*[0-9\.]+)(px|em)\s*\)/gi,
  64                 other: /\([^\)]*\)/g
  65         };
  66
  67         //expose media query support flag for external use
  68         respond.mediaQueriesSupported = w.matchMedia && w.matchMedia( "only all" ) !== null && w.matchMedia( "only all" ).matches;
  69
  70         //if media queries are supported, exit here
  71         if( respond.mediaQueriesSupported ){
  72                 return;
  73         }
  74
  75         //define vars
  76         var doc = w.document,
  77                 docElem = doc.documentElement,
  78                 mediastyles = [],
  79                 rules = [],
  80                 appendedEls = [],
  81                 parsedSheets = {},
  82                 resizeThrottle = 30,
  83                 head = doc.getElementsByTagName( "head" )[0] || docElem,
  84                 base = doc.getElementsByTagName( "base" )[0],
  85                 links = head.getElementsByTagName( "link" ),
  86
  87                 lastCall,
  88                 resizeDefer,
  89
  90                 //cached container for 1em value, populated the first time it's needed
  91                 eminpx,
  92
  93                 // returns the value of 1em in pixels
  94                 getEmValue = function() {
  95                         var ret,
  96                                 div = doc.createElement('div'),
  97                                 body = doc.body,
  98                                 originalHTMLFontSize = docElem.style.fontSize,
  99                                 originalBodyFontSize = body && body.style.fontSize,
 100                                 fakeUsed = false;
 101
 102                         div.style.cssText = "position:absolute;font-size:1em;width:1em";
 103
 104                         if( !body ){
 105                                 body = fakeUsed = doc.createElement( "body" );
 106                                 body.style.background = "none";
 107                         }
 108
 109                         // 1em in a media query is the value of the default font size of the browser
 110                         // reset docElem and body to ensure the correct value is returned
 111                         docElem.style.fontSize = "100%";
 112                         body.style.fontSize = "100%";
 113
 114                         body.appendChild( div );
 115
 116                         if( fakeUsed ){
 117                                 docElem.insertBefore( body, docElem.firstChild );
 118                         }
 119
 120                         ret = div.offsetWidth;
 121
 122                         if( fakeUsed ){
 123                                 docElem.removeChild( body );
 124                         }
 125                         else {
 126                                 body.removeChild( div );
 127                         }
 128
 129                         // restore the original values
 130                         docElem.style.fontSize = originalHTMLFontSize;
 131                         if( originalBodyFontSize ) {
 132                                 body.style.fontSize = originalBodyFontSize;
 133                         }
 134
 135
 136                         //also update eminpx before returning
 137                         ret = eminpx = parseFloat(ret);
 138
 139                         return ret;
 140                 },
 141
 142                 //enable/disable styles
 143                 applyMedia = function( fromResize ){
 144                         var name = "clientWidth",
 145                                 docElemProp = docElem[ name ],
 146                                 currWidth = doc.compatMode === "CSS1Compat" && docElemProp || doc.body[ name ] || docElemProp,
 147                                 styleBlocks     = {},
 148                                 lastLink = links[ links.length-1 ],
 149                                 now = (new Date()).getTime();
 150
 151                         //throttle resize calls
 152                         if( fromResize && lastCall && now - lastCall < resizeThrottle ){
 153                                 w.clearTimeout( resizeDefer );
 154                                 resizeDefer = w.setTimeout( applyMedia, resizeThrottle );
 155                                 return;
 156                         }
 157                         else {
 158                                 lastCall = now;
 159                         }
 160
 161                         for( var i in mediastyles ){
 162                                 if( mediastyles.hasOwnProperty( i ) ){
 163                                         var thisstyle = mediastyles[ i ],
 164                                                 min = thisstyle.minw,
 165                                                 max = thisstyle.maxw,
 166                                                 minnull = min === null,
 167                                                 maxnull = max === null,
 168                                                 em = "em";
 169
 170                                         if( !!min ){
 171                                                 min = parseFloat( min ) * ( min.indexOf( em ) > -1 ? ( eminpx || getEmValue() ) : 1 );
 172                                         }
 173                                         if( !!max ){
 174                                                 max = parseFloat( max ) * ( max.indexOf( em ) > -1 ? ( eminpx || getEmValue() ) : 1 );
 175                                         }
 176
 177                                         // 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
 178                                         if( !thisstyle.hasquery || ( !minnull || !maxnull ) && ( minnull || currWidth >= min ) && ( maxnull || currWidth <= max ) ){
 179                                                 if( !styleBlocks[ thisstyle.media ] ){
 180                                                         styleBlocks[ thisstyle.media ] = [];
 181                                                 }
 182                                                 styleBlocks[ thisstyle.media ].push( rules[ thisstyle.rules ] );
 183                                         }
 184                                 }
 185                         }
 186
 187                         //remove any existing respond style element(s)
 188                         for( var j in appendedEls ){
 189                                 if( appendedEls.hasOwnProperty( j ) ){
 190                                         if( appendedEls[ j ] && appendedEls[ j ].parentNode === head ){
 191                                                 head.removeChild( appendedEls[ j ] );
 192                                         }
 193                                 }
 194                         }
 195                         appendedEls.length = 0;
 196
 197                         //inject active styles, grouped by media type
 198                         for( var k in styleBlocks ){
 199                                 if( styleBlocks.hasOwnProperty( k ) ){
 200                                         var ss = doc.createElement( "style" ),
 201                                                 css = styleBlocks[ k ].join( "\n" );
 202
 203                                         ss.type = "text/css";
 204                                         ss.media = k;
 205
 206                                         //originally, ss was appended to a documentFragment and sheets were appended in bulk.
 207                                         //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!
 208                                         head.insertBefore( ss, lastLink.nextSibling );
 209
 210                                         if ( ss.styleSheet ){
 211                                                 ss.styleSheet.cssText = css;
 212                                         }
 213                                         else {
 214                                                 ss.appendChild( doc.createTextNode( css ) );
 215                                         }
 216
 217                                         //push to appendedEls to track for later removal
 218                                         appendedEls.push( ss );
 219                                 }
 220                         }
 221                 },
 222                 //find media blocks in css text, convert to style blocks
 223                 translate = function( styles, href, media ){
 224                         var qs = styles.replace( respond.regex.comments, '' )
 225                                         .replace( respond.regex.keyframes, '' )
 226                                         .match( respond.regex.media ),
 227                                 ql = qs && qs.length || 0;
 228
 229                         //try to get CSS path
 230                         href = href.substring( 0, href.lastIndexOf( "/" ) );
 231
 232                         var repUrls = function( css ){
 233                                         return css.replace( respond.regex.urls, "$1" + href + "$2$3" );
 234                                 },
 235                                 useMedia = !ql && media;
 236
 237                         //if path exists, tack on trailing slash
 238                         if( href.length ){ href += "/"; }
 239
 240                         //if no internal queries exist, but media attr does, use that
 241                         //note: this currently lacks support for situations where a media attr is specified on a link AND
 242                                 //its associated stylesheet has internal CSS media queries.
 243                                 //In those cases, the media attribute will currently be ignored.
 244                         if( useMedia ){
 245                                 ql = 1;
 246                         }
 247
 248                         for( var i = 0; i < ql; i++ ){
 249                                 var fullq, thisq, eachq, eql;
 250
 251                                 //media attr
 252                                 if( useMedia ){
 253                                         fullq = media;
 254                                         rules.push( repUrls( styles ) );
 255                                 }
 256                                 //parse for styles
 257                                 else{
 258                                         fullq = qs[ i ].match( respond.regex.findStyles ) && RegExp.$1;
 259                                         rules.push( RegExp.$2 && repUrls( RegExp.$2 ) );
 260                                 }
 261
 262                                 eachq = fullq.split( "," );
 263                                 eql = eachq.length;
 264
 265                                 for( var j = 0; j < eql; j++ ){
 266                                         thisq = eachq[ j ];
 267
 268                                         if( isUnsupportedMediaQuery( thisq ) ) {
 269                                                 continue;
 270                                         }
 271
 272                                         mediastyles.push( {
 273                                                 media : thisq.split( "(" )[ 0 ].match( respond.regex.only ) && RegExp.$2 || "all",
 274                                                 rules : rules.length - 1,
 275                                                 hasquery : thisq.indexOf("(") > -1,
 276                                                 minw : thisq.match( respond.regex.minw ) && parseFloat( RegExp.$1 ) + ( RegExp.$2 || "" ),
 277                                                 maxw : thisq.match( respond.regex.maxw ) && parseFloat( RegExp.$1 ) + ( RegExp.$2 || "" )
 278                                         } );
 279                                 }
 280                         }
 281
 282                         applyMedia();
 283                 },
 284
 285                 //recurse through request queue, get css text
 286                 makeRequests = function(){
 287                         if( requestQueue.length ){
 288                                 var thisRequest = requestQueue.shift();
 289
 290                                 ajax( thisRequest.href, function( styles ){
 291                                         translate( styles, thisRequest.href, thisRequest.media );
 292                                         parsedSheets[ thisRequest.href ] = true;
 293
 294                                         // by wrapping recursive function call in setTimeout
 295                                         // we prevent "Stack overflow" error in IE7
 296                                         w.setTimeout(function(){ makeRequests(); },0);
 297                                 } );
 298                         }
 299                 },
 300
 301                 //loop stylesheets, send text content to translate
 302                 ripCSS = function(){
 303
 304                         for( var i = 0; i < links.length; i++ ){
 305                                 var sheet = links[ i ],
 306                                 href = sheet.href,
 307                                 media = sheet.media,
 308                                 isCSS = sheet.rel && sheet.rel.toLowerCase() === "stylesheet";
 309
 310                                 //only links plz and prevent re-parsing
 311                                 if( !!href && isCSS && !parsedSheets[ href ] ){
 312                                         // selectivizr exposes css through the rawCssText expando
 313                                         if (sheet.styleSheet && sheet.styleSheet.rawCssText) {
 314                                                 translate( sheet.styleSheet.rawCssText, href, media );
 315                                                 parsedSheets[ href ] = true;
 316                                         } else {
 317                                                 if( (!/^([a-zA-Z:]*\/\/)/.test( href ) && !base) ||
 318                                                         href.replace( RegExp.$1, "" ).split( "/" )[0] === w.location.host ){
 319                                                         // IE7 doesn't handle urls that start with '//' for ajax request
 320                                                         // manually add in the protocol
 321                                                         if ( href.substring(0,2) === "//" ) { href = w.location.protocol + href; }
 322                                                         requestQueue.push( {
 323                                                                 href: href,
 324                                                                 media: media
 325                                                         } );
 326                                                 }
 327                                         }
 328                                 }
 329                         }
 330                         makeRequests();
 331                 };
 332
 333         //translate CSS
 334         ripCSS();
 335
 336         //expose update for re-running respond later on
 337         respond.update = ripCSS;
 338
 339         //expose getEmValue
 340         respond.getEmValue = getEmValue;
 341
 342         //adjust on resize
 343         function callMedia(){
 344                 applyMedia( true );
 345         }
 346
 347         if( w.addEventListener ){
 348                 w.addEventListener( "resize", callMedia, false );
 349         }
 350         else if( w.attachEvent ){
 351                 w.attachEvent( "onresize", callMedia );
 352         }
 353 })(this);