ie6不支持png图片的解决办法
在head里引入png.js文件
<!--[if lte IE 6]>
<script type="text/javascript" src="js/PNG.js"></script>
<script>
PNG.fix('*');
</script>
<![endif]-->
png.js文件内容如下：、
/** * PNG: 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/PNG/ * Version: 0.0.7a * Licensed under the MIT License: http://dillerdesign.com/experiment/PNG/#license * * Example usage: * PNG.fix('.png_bg'); // argument is a CSS selector * PNG.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 PNG = { ns: 'PNG', 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() { PNG = 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) { PNG.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) { PNG.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 */ PNG.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(PNG.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 = PNG; 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) {} PNG.createVmlNameSpace(); PNG.createVmlStyleSheet();// JavaScript Document
