/**







* DD_belatedPNG: Adds IE6 support: PNG images for CSS background-image and HTML <IMG/>.







* Author: Drew Diller







* Email: drew.diller@gmail.com







* URL: http://www.dillerdesign.com/experiment/DD_belatedPNG/







* Version: 0.0.7a







* Licensed under the MIT License: http://dillerdesign.com/experiment/DD_belatedPNG/#license







*







* Example usage:







* DD_belatedPNG.fix('.png_bg'); // argument is a CSS selector







* DD_belatedPNG.fixPng( someNode ); // argument is an HTMLDomElement







**/















/*







PLEASE READ:







Absolutely everything in this script is SILLY.  I know this.  IE's rendering of certain pixels doesn't make sense, so neither does this code!







*/















var DD_belatedPNG = {















	ns: 'DD_belatedPNG',







	imgSize: {},







	







	createVmlNameSpace: function() { /* enable VML */







		if (document.namespaces && !document.namespaces[this.ns]) {







		  document.namespaces.add(this.ns, 'urn:schemas-microsoft-com:vml');







		}







		if (window.attachEvent) {







			window.attachEvent('onbeforeunload', function() {







				DD_belatedPNG = null;







			});







		}







	},







	







	createVmlStyleSheet: function() { /* style VML, enable behaviors */







		/*







			Just in case lots of other developers have added







			lots of other stylesheets using document.createStyleSheet







			and hit the 31-limit mark, let's not use that method!







			further reading: http://msdn.microsoft.com/en-us/library/ms531194(VS.85).aspx







		*/







		var style = document.createElement('style');







		document.documentElement.firstChild.insertBefore(style, document.documentElement.firstChild.firstChild);







		var styleSheet = style.styleSheet;







		styleSheet.addRule(this.ns + '\\:*', '{behavior:url(#default#VML)}');







		styleSheet.addRule(this.ns + '\\:shape', 'position:absolute;');







		styleSheet.addRule('img.' + this.ns + '_sizeFinder', 'behavior:none; border:none; position:absolute; z-index:-1; top:-10000px; visibility:hidden;'); /* large negative top value for avoiding vertical scrollbars for large images, suggested by James O'Brien, http://www.thanatopsic.org/hendrik/ */







		this.styleSheet = styleSheet;







	},







	







	readPropertyChange: function() {







		var el = event.srcElement;







		if (event.propertyName.search('background') != -1 || event.propertyName.search('border') != -1) {







			DD_belatedPNG.applyVML(el);







		}







		if (event.propertyName == 'style.display') {







			var display = (el.currentStyle.display == 'none') ? 'none' : 'block';







			for (var v in el.vml) {







				el.vml[v].shape.style.display = display;







			}







		}







		if (event.propertyName.search('filter') != -1) {







			DD_belatedPNG.vmlOpacity(el);







		}







	},







	







	vmlOpacity: function(el) {







		if (el.currentStyle.filter.search('lpha') != -1) {







			var trans = el.currentStyle.filter;







			trans = parseInt(trans.substring(trans.lastIndexOf('=')+1, trans.lastIndexOf(')')), 10)/100;







			el.vml.color.shape.style.filter = el.currentStyle.filter; /* complete guesswork */







			el.vml.image.fill.opacity = trans; /* complete guesswork */







		}







	},







	







	handlePseudoHover: function(el) {







		setTimeout(function() { /* wouldn't work as intended without setTimeout */







			DD_belatedPNG.applyVML(el);







		}, 1);







	},







	







	/**







	* This is the method to use in a document.







	* @param {String} selector - REQUIRED - a CSS selector, such as '#doc .container'







	**/







	fix: function(selector) {







		var selectors = selector.split(','); /* multiple selectors supported, no need for multiple calls to this anymore */







		for (var i=0; i<selectors.length; i++) {







			this.styleSheet.addRule(selectors[i], 'behavior:expression(DD_belatedPNG.fixPng(this))'); /* seems to execute the function without adding it to the stylesheet - interesting... */







		}







	},







	







	applyVML: function(el) {







		el.runtimeStyle.cssText = '';







		this.vmlFill(el);







		this.vmlOffsets(el);







		this.vmlOpacity(el);







		if (el.isImg) {







			this.copyImageBorders(el);







		}







	},







	







	attachHandlers: function(el) {







		var self = this;







		var handlers = {resize: 'vmlOffsets', move: 'vmlOffsets'};







		if (el.nodeName == 'A') {







			var moreForAs = {mouseleave: 'handlePseudoHover', mouseenter: 'handlePseudoHover', focus: 'handlePseudoHover', blur: 'handlePseudoHover'};







			for (var a in moreForAs) {







				handlers[a] = moreForAs[a];







			}







		}







		for (var h in handlers) {







			el.attachEvent('on' + h, function() {







				self[handlers[h]](el);







			});







		}







		el.attachEvent('onpropertychange', this.readPropertyChange);







	},







	







	giveLayout: function(el) {







		el.style.zoom = 1;







		if (el.currentStyle.position == 'static') {







			el.style.position = 'relative';







		}







	},







	







	copyImageBorders: function(el) {







		var styles = {'borderStyle':true, 'borderWidth':true, 'borderColor':true};







		for (var s in styles) {







			el.vml.color.shape.style[s] = el.currentStyle[s];







		}







	},







	







	vmlFill: function(el) {







		if (!el.currentStyle) {







			return;







		} else {







			var elStyle = el.currentStyle;







		}







		for (var v in el.vml) {







			el.vml[v].shape.style.zIndex = elStyle.zIndex;







		}







		el.runtimeStyle.backgroundColor = '';







		el.runtimeStyle.backgroundImage = '';







		var noColor = (elStyle.backgroundColor == 'transparent');







		var noImg = true;







		if (elStyle.backgroundImage != 'none' || el.isImg) {







			if (!el.isImg) {







				el.vmlBg = elStyle.backgroundImage;







				el.vmlBg = el.vmlBg.substr(5, el.vmlBg.lastIndexOf('")')-5);







			}







			else {







				el.vmlBg = el.src;







			}







			var lib = this;







			if (!lib.imgSize[el.vmlBg]) { /* determine size of loaded image */







				var img = document.createElement('img');







				lib.imgSize[el.vmlBg] = img;







				img.className = lib.ns + '_sizeFinder';







				img.runtimeStyle.cssText = 'behavior:none; position:absolute; left:-10000px; top:-10000px; border:none;'; /* make sure to set behavior to none to prevent accidental matching of the helper elements! */







				img.attachEvent('onload', function() {







					this.width = this.offsetWidth; /* weird cache-busting requirement! */







					this.height = this.offsetHeight;







					lib.vmlOffsets(el);







				});







				img.src = el.vmlBg;







				img.removeAttribute('width');







				img.removeAttribute('height');







				document.body.insertBefore(img, document.body.firstChild);







			}







			el.vml.image.fill.src = el.vmlBg;







			noImg = false;







		}







		el.vml.image.fill.on = !noImg;







		el.vml.image.fill.color = 'none';







		el.vml.color.shape.style.backgroundColor = elStyle.backgroundColor;







		el.runtimeStyle.backgroundImage = 'none';







		el.runtimeStyle.backgroundColor = 'transparent';







	},







	







	/* IE can't figure out what do when the offsetLeft and the clientLeft add up to 1, and the VML ends up getting fuzzy... so we have to push/enlarge things by 1 pixel and then clip off the excess */







	vmlOffsets: function(el) {







		var thisStyle = el.currentStyle;







		var size = {'W':el.clientWidth+1, 'H':el.clientHeight+1, 'w':this.imgSize[el.vmlBg].width, 'h':this.imgSize[el.vmlBg].height, 'L':el.offsetLeft, 'T':el.offsetTop, 'bLW':el.clientLeft, 'bTW':el.clientTop};







		var fudge = (size.L + size.bLW == 1) ? 1 : 0;







		







		/* vml shape, left, top, width, height, origin */







		var makeVisible = function(vml, l, t, w, h, o) {







			vml.coordsize = w+','+h;







			vml.coordorigin = o+','+o;







			vml.path = 'm0,0l'+w+',0l'+w+','+h+'l0,'+h+' xe';







			vml.style.width = w + 'px';







			vml.style.height = h + 'px';







			vml.style.left = l + 'px';







			vml.style.top = t + 'px';







		};







		makeVisible(el.vml.color.shape, (size.L + (el.isImg ? 0 : size.bLW)), (size.T + (el.isImg ? 0 : size.bTW)), (size.W-1), (size.H-1), 0);







		makeVisible(el.vml.image.shape, (size.L + size.bLW), (size.T + size.bTW), (size.W), (size.H), 1);







		







		var bg = {'X':0, 'Y':0};







		var figurePercentage = function(axis, position) {







			var fraction = true;







			switch(position) {







				case 'left':







				case 'top':







					bg[axis] = 0;







					break;







				case 'center':







					bg[axis] = .5;







					break;







				case 'right':







				case 'bottom':







					bg[axis] = 1;







					break;







				default:







					if (position.search('%') != -1) {







						bg[axis] = parseInt(position)*.01;







					}







					else {







						fraction = false;







					}







			}







			var horz = (axis == 'X');







			bg[axis] = Math.ceil(fraction ? ( (size[horz?'W': 'H'] * bg[axis]) - (size[horz?'w': 'h'] * bg[axis]) ) : parseInt(position));







			if (bg[axis] == 0) {







				bg[axis]++;







			}







		};







		for (var b in bg) {







			figurePercentage(b, thisStyle['backgroundPosition'+b]);







		}







		







		el.vml.image.fill.position = (bg.X/size.W) + ',' + (bg.Y/size.H);







		







		var bgR = thisStyle.backgroundRepeat;







		var dC = {'T':1, 'R':size.W+fudge, 'B':size.H, 'L':1+fudge}; /* these are defaults for repeat of any kind */







		var altC = { 'X': {'b1': 'L', 'b2': 'R', 'd': 'W'}, 'Y': {'b1': 'T', 'b2': 'B', 'd': 'H'} };







		if (bgR != 'repeat') {







			var c = {'T':(bg.Y), 'R':(bg.X+size.w), 'B':(bg.Y+size.h), 'L':(bg.X)}; /* these are defaults for no-repeat - clips down to the image location */







			if (bgR.search('repeat-') != -1) { /* now let's revert to dC for repeat-x or repeat-y */







				var v = bgR.split('repeat-')[1].toUpperCase();







				c[altC[v].b1] = 1;







				c[altC[v].b2] = size[altC[v].d];







			}







			if (c.B > size.H) {







				c.B = size.H;







			}







			el.vml.image.shape.style.clip = 'rect('+c.T+'px '+(c.R+fudge)+'px '+c.B+'px '+(c.L+fudge)+'px)';







		}







		else {







			el.vml.image.shape.style.clip = 'rect('+dC.T+'px '+dC.R+'px '+dC.B+'px '+dC.L+'px)';







		}







	},







	







	fixPng: function(el) {







		el.style.behavior = 'none';







		if (el.nodeName == 'BODY' || el.nodeName == 'TD' || el.nodeName == 'TR') { /* elements not supported yet */







			return;







		}







		el.isImg = false;







		if (el.nodeName == 'IMG') {







			if(el.src.toLowerCase().search(/\.png$/) != -1) {







				el.isImg = true;







				el.style.visibility = 'hidden';







			}







			else {







				return;







			}







		}







		else if (el.currentStyle.backgroundImage.toLowerCase().search('.png') == -1) {







			return;







		}







		var lib = DD_belatedPNG;







		el.vml = {color: {}, image: {}};







		var els = {shape: {}, fill: {}};







		for (var r in el.vml) {







			for (var e in els) {







				var nodeStr = lib.ns + ':' + e;







				el.vml[r][e] = document.createElement(nodeStr);







			}







			el.vml[r].shape.stroked = false;







			el.vml[r].shape.appendChild(el.vml[r].fill);







			el.parentNode.insertBefore(el.vml[r].shape, el);







		}







		el.vml.image.shape.fillcolor = 'none'; /* Don't show blank white shapeangle when waiting for image to load. */







		el.vml.image.fill.type = 'tile'; /* Ze magic!! Makes image show up. */







		el.vml.color.fill.on = false; /* Actually going to apply vml element's style.backgroundColor, so hide the whiteness. */







		







		lib.attachHandlers(el);







		







		lib.giveLayout(el);







		lib.giveLayout(el.offsetParent);







		







		/* set up element */







		lib.applyVML(el);







	}







	







};







try {







	document.execCommand("BackgroundImageCache", false, true); /* TredoSoft Multiple IE doesn't like this, so try{} it */







} catch(r) {}







DD_belatedPNG.createVmlNameSpace();







DD_belatedPNG.createVmlStyleSheet();















/* EXAMPLE */















/* string argument can be any CSS selector */







/* .png_bg example is unnecessary */







/* change it to what suits you! */