pakpenyo/matchMedia - IE8

## matchMedia - IE8
/*! matchMedia() polyfill - Test a CSS media type/query in JS. Authors & copyright (c) 2012: Scott Jehl, Paul Irish, Nicholas Zakas. Dual MIT/BSD license - IE8 VERSION! */
window.matchMedia = window.matchMedia || (function(doc, undefined){

  var 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);

  var mqRun = function ( mq ) {
    div.innerHTML = '&shy;<style media="' + mq + '"> #mq-test-1 { width: 42px; }</style>';
    docElem.insertBefore( fakeBody, refNode );
    bool = div.offsetWidth === 42;
    docElem.removeChild( fakeBody );

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

  getEmValue = function () {
    var ret,
        body = docElem.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 );

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

    //also update eminpx before returning
    ret = eminpx = parseFloat( div.offsetWidth );

    return ret;
  },

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

  // verify that we have support for a simple media query
  mqSupport = mqRun( '(min-width: 0px)' ).matches;

  return function ( mq ) {
    if( mqSupport ) {
      return mqRun( mq );
    } else {
      if (doc.body) {
	      var min = mq.match( /\(min\-width:[\s]*([\s]*[0-9\.]+)(px|em)[\s]*\)/ ) && parseFloat( RegExp.$1 ) + ( RegExp.$2 || "" ),
	          max = mq.match( /\(max\-width:[\s]*([\s]*[0-9\.]+)(px|em)[\s]*\)/ ) && parseFloat( RegExp.$1 ) + ( RegExp.$2 || "" ),
	          minnull = min === null,
	          maxnull = max === null,
	          currWidth = doc.body.offsetWidth,
	          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 ); }

	      bool = ( !minnull || !maxnull ) && ( minnull || currWidth >= min ) && ( maxnull || currWidth <= max );

	      return { matches: bool, media: mq };
	   } else {
		   return { matches: false, media: {} };
	   }
    }
  };

}( document ));

/*! matchMedia() polyfill addListener/removeListener extension. Author & copyright (c) 2012: Scott Jehl. Dual MIT/BSD license - IE8 VERSION! */
(function(){
	// monkeypatch unsupported addListener/removeListener with polling
	if(typeof window.matchMedia( "" ) !== "undefined"){
		var oldMM = window.matchMedia;

		window.matchMedia = function( q ){
			var ret = oldMM( q ),
				listeners = [],
				last = false,
				timer,
				check = function(){
					var list = oldMM( q ),
						unmatchToMatch = list.matches && !last,
						matchToUnmatch = !list.matches && last;

                                        //fire callbacks only if transitioning to or from matched state
					if( unmatchToMatch || matchToUnmatch ){
						for( var i =0, il = listeners.length; i< il; i++ ){
							listeners[ i ].call( ret, list );
						}
					}
					last = list.matches;
				};

			ret.addListener = function( cb ){
				listeners.push( cb );
				if( !timer ){
					timer = setInterval( check, 1000 );
				}
			};

			ret.removeListener = function( cb ){
				for( var i =0, il = listeners.length; i< il; i++ ){
					if( listeners[ i ] === cb ){
						listeners.splice( i, 1 );
					}
				}
				if( !listeners.length && timer ){
					clearInterval( timer );
				}
			};

			return ret;
		};
	}
}());
	/! matchMedia() polyfill - Test a CSS media type/query in JS. Authors & copyright (c) 2012: Scott Jehl, Paul Irish, Nicholas Zakas. Dual MIT/BSD license - IE8 VERSION! /
	window.matchMedia = window.matchMedia \|\| (function(doc, undefined){

	var 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);

	var mqRun = function ( mq ) {
	div.innerHTML = '<style media="' + mq + '"> #mq-test-1 { width: 42px; }</style>';
	docElem.insertBefore( fakeBody, refNode );
	bool = div.offsetWidth === 42;
	docElem.removeChild( fakeBody );

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

	getEmValue = function () {
	var ret,
	body = docElem.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 );

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

	//also update eminpx before returning
	ret = eminpx = parseFloat( div.offsetWidth );

	return ret;
	},

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

	// verify that we have support for a simple media query
	mqSupport = mqRun( '(min-width: 0px)' ).matches;

	return function ( mq ) {
	if( mqSupport ) {
	return mqRun( mq );
	} else {
	if (doc.body) {
	var min = mq.match( /\(min\-width:[\s]([\s][0-9\.]+)(px\|em)[\s]*\)/ ) && parseFloat( RegExp.$1 ) + ( RegExp.$2 \|\| "" ),
	max = mq.match( /\(max\-width:[\s]([\s][0-9\.]+)(px\|em)[\s]*\)/ ) && parseFloat( RegExp.$1 ) + ( RegExp.$2 \|\| "" ),
	minnull = min === null,
	maxnull = max === null,
	currWidth = doc.body.offsetWidth,
	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 ); }

	bool = ( !minnull \|\| !maxnull ) && ( minnull \|\| currWidth >= min ) && ( maxnull \|\| currWidth <= max );

	return { matches: bool, media: mq };
	} else {
	return { matches: false, media: {} };
	}
	}
	};

	}( document ));

	/! matchMedia() polyfill addListener/removeListener extension. Author & copyright (c) 2012: Scott Jehl. Dual MIT/BSD license - IE8 VERSION! /
	(function(){
	// monkeypatch unsupported addListener/removeListener with polling
	if(typeof window.matchMedia( "" ) !== "undefined"){
	var oldMM = window.matchMedia;

	window.matchMedia = function( q ){
	var ret = oldMM( q ),
	listeners = [],
	last = false,
	timer,
	check = function(){
	var list = oldMM( q ),
	unmatchToMatch = list.matches && !last,
	matchToUnmatch = !list.matches && last;

	//fire callbacks only if transitioning to or from matched state
	if( unmatchToMatch \|\| matchToUnmatch ){
	for( var i =0, il = listeners.length; i< il; i++ ){
	listeners[ i ].call( ret, list );
	}
	}
	last = list.matches;
	};

	ret.addListener = function( cb ){
	listeners.push( cb );
	if( !timer ){
	timer = setInterval( check, 1000 );
	}
	};

	ret.removeListener = function( cb ){
	for( var i =0, il = listeners.length; i< il; i++ ){
	if( listeners[ i ] === cb ){
	listeners.splice( i, 1 );
	}
	}
	if( !listeners.length && timer ){
	clearInterval( timer );
	}
	};

	return ret;
	};
	}
	}());