/*
* respond.js - A small and fast polyfill for min/max-width CSS3 Media Queries
* Copyright 2011, Scott Jehl, scottjehl.com
* Dual licensed under the MIT or GPL Version 2 licenses.
* Usage: Check out the readme file or github.com/scottjehl/respond
*/
(function( win, mqSupported ){
//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 = mqSupported;
//if media queries are supported, exit here
if( mqSupported ){ return; }
//define vars
var doc = win.document,
docElem = doc.documentElement,
mediastyles = [],
rules = [],
appendedEls = [],
parsedSheets = {},
resizeThrottle = 30,
head = doc.getElementsByTagName( "head" )[0] || docElem,
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 ] ){
if( !/^([a-zA-Z]+?:(\/\/)?(www\.)?)/.test( href )
|| href.replace( RegExp.$1, "" ).split( "/" )[0] === win.location.host ){
requestQueue.push( {
href: href,
media: media
} );
}
else{
parsedSheets[ href ] = true;
}
}
}
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 ([^\{]+)\{((?!@media)[\s\S])*(?=\}[\s]*\/\*\/mediaquery\*\/)/gmi ),
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.match( /(only\s+)?([a-zA-Z]+)(\sand)?/ ) && RegExp.$2,
rules : rules.length - 1,
minw : thisq.match( /\(min\-width:[\s]*([\s]*[0-9]+)px[\s]*\)/ ) && parseFloat( RegExp.$1 ),
maxw : thisq.match( /\(max\-width:[\s]*([\s]*[0-9]+)px[\s]*\)/ ) && parseFloat( RegExp.$1 )
} );
}
}
applyMedia();
},
lastCall,
resizeDefer,
//enable/disable styles
applyMedia = function( fromResize ){
var name = "clientWidth",
docElemProp = docElem[ name ],
currWidth = doc.compatMode === "CSS1Compat" && docElemProp || doc.body[ name ] || docElemProp,
styleBlocks = {},
dFrag = doc.createDocumentFragment(),
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 ];
if( !thisstyle.minw && !thisstyle.maxw ||
( !thisstyle.minw || thisstyle.minw && currWidth >= thisstyle.minw ) &&
(!thisstyle.maxw || thisstyle.maxw && currWidth <= thisstyle.maxw ) ){
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;
if ( ss.styleSheet ){
ss.styleSheet.cssText = css;
}
else {
ss.appendChild( doc.createTextNode( css ) );
}
dFrag.appendChild( ss );
appendedEls.push( ss );
}
//append to DOM at once
head.insertBefore( dFrag, lastLink.nextSibling );
},
//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();
},
//define ajax obj
xmlHttp = (function() {
var xmlhttpmethod = false,
attempts = [
function(){ return new ActiveXObject("Microsoft.XMLHTTP") },
function(){ return new XMLHttpRequest() }
],
al = attempts.length;
while( al-- ){
try {
xmlhttpmethod = attempts[ al ]();
}
catch(e) {
continue;
}
break;
}
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,
(function( win ){
//for speed, flag browsers with window.matchMedia support and IE 9 as supported
if( win.matchMedia ){ return true; }
var bool,
doc = document,
docElem = doc.documentElement,
refNode = docElem.firstElementChild || docElem.firstChild,
// fakeBody required for <FF4 when executed in <head>
fakeUsed = !doc.body,
fakeBody = doc.body || doc.createElement( "body" ),
div = doc.createElement( "div" ),
q = "only all";
div.id = "mq-test-1";
div.style.cssText = "position:absolute;top:-99em";
fakeBody.appendChild( div );
div.innerHTML = '_<style media="'+q+'"> #mq-test-1 { width: 9px; }</style>';
if( fakeUsed ){
docElem.insertBefore( fakeBody, refNode );
}
div.removeChild( div.firstChild );
bool = div.offsetWidth == 9;
if( fakeUsed ){
docElem.removeChild( fakeBody );
}
else{
fakeBody.removeChild( div );
}
return bool;
})( this )
);