常见css的兼容问题

链接的虚线框问题

<!-- html -->
<a class="noDashedBox" href="#"><img src="http://j5.dfcfw.com/image/201406/20140603152217.png" /></a>

/*
 * a, img, input等标签点击时会带有虚线框
 * 去除它
*/
.noDashedBox {
    outline:0;
    blur:expression(this.onFocus=this.blur());
}

固定定位

<!-- html -->
<a class="fixedTop" href="#"><img src="http://j5.dfcfw.com/image/201406/20140603152217.png" /></a>

<a class="fixedBottom" href="#"><img src="http://j5.dfcfw.com/image/201406/20140603152217.png" /></a>

/*  css  */
.fixedTop {
    position:fixed;
    top:100px;
    left:50%;
    margin-left:500px;
    _position:absolute;
    _top:expression(eval(document.documentElement.scrollTop + 100));
}

.fixedBottom {
    position:fixed;
    bottom:50px;
    left:50%;
    margin-left:500px;
    _position:absolute;
    _top:expression(eval(document.documentElement.scrollTop + document.documentElement.clientHeight - 70));
}

/* ie6 调动问题 */
body {
  _background-attachment: fixed;
  _background-image: url(about:blank);
}

png背景图片透明：for ie6

<!-- html -->
<div class="pngOpacity"></div>

/*
 * http://www.zhangxinxu.com/wordpress/2009/08/ +
 * ie6%E4%B8%8Bpng%E8%83%8C%E6%99%AF%E4%B8%8D%E9%80%8F%E6%98%8E%E9%97%AE%E9%A2%98%E7%9A%84%E7%BB%BC%E5%90%88%E6%8B%93%E5%B1%95/
 *
 * ie6 png8 background 不能定位
*/
.pngOpacity {
    height:228px;
    background:url(http://www.zhangxinxu.com/study/image/png_test.png) no-repeat;
    _background:none;
    _filter:progid:DXImageTransform.Microsoft.AlphaImageLoader(enabled='true', sizingMethod='crop', src='http://www.zhangxinxu.com/study/image/png_test.png');
}

// png透明的js解决方案  http://www.zhangxinxu.com/study/js/png.js
if (!window.XMLHttpRequest) {
    window.attachEvent("onload", enableAlphaImages);
}

function enableAlphaImages(){
    for (var i=0; i<document.all.length; i++){
            var obj = document.all[i];
            var bg = obj.currentStyle.backgroundImage;
            var img = document.images[i];
            if (bg && bg.match(/.png/i) != null) {
                var img = bg.substring(5,bg.length-2);
                var offset = obj.style["background-position"];
                obj.style.filter = "progid:DXImageTransform.Microsoft.AlphaImageLoader(src='"+img+"', sizingMethod='crop')";
                obj.style.background = "none";
        } else if (img && img.src.match(/.png$/i) != null) {
            var src = img.src;
            img.style.width = img.width + "px";
            img.style.height = img.height + "px";
            img.style.filter ="progid:DXImageTransform.Microsoft.AlphaImageLoader(src='"+src+"', sizingMethod='crop')"
            img.src = "http://s1.95171.cn/b/img/pixel.gif"; //替换透明PNG的图片

 } } }

ie6 png 图片透明的另外一段js代码

/*
 * ie6_png.js
 * <!--[if ie 6]><script src="ie6_png.js"></script><![endif]-->
 * 如此在头部插入即可
*/
var DD_belatedPNG={ns:"DD_belatedPNG",imgSize:{},delay:10,nodesFixed:0,createVmlNameSpace:function(){if(document.namespaces&&!document.namespaces[this.ns]){document.namespaces.add(this.ns,"urn:schemas-microsoft-com:vml")}},createVmlStyleSheet:function(){var b,a;b=document.createElement("style");b.setAttribute("media","screen");document.documentElement.firstChild.insertBefore(b,document.documentElement.firstChild.firstChild);if(b.styleSheet){b=b.styleSheet;b.addRule(this.ns+"\:*","{behavior:url(#default#VML)}");b.addRule(this.ns+"\:shape","position:absolute;");b.addRule("img."+this.ns+"_sizeFinder","behavior:none; border:none; position:absolute; z-index:-1; top:-10000px; visibility:hidden;");this.screenStyleSheet=b;a=document.createElement("style");a.setAttribute("media","print");document.documentElement.firstChild.insertBefore(a,document.documentElement.firstChild.firstChild);a=a.styleSheet;a.addRule(this.ns+"\:*","{display: none !important;}");a.addRule("img."+this.ns+"_sizeFinder","{display: none !important;}")}},readPropertyChange:function(){var b,c,a;b=event.srcElement;if(!b.vmlInitiated){return}if(event.propertyName.search("background")!=-1||event.propertyName.search("border")!=-1){DD_belatedPNG.applyVML(b)}if(event.propertyName=="style.display"){c=(b.currentStyle.display=="none")?"none":"block";for(a in b.vml){if(b.vml.hasOwnProperty(a)){b.vml[a].shape.style.display=c}}}if(event.propertyName.search("filter")!=-1){DD_belatedPNG.vmlOpacity(b)}},vmlOpacity:function(b){if(b.currentStyle.filter.search("lpha")!=-1){var a=b.currentStyle.filter;a=parseInt(a.substring(a.lastIndexOf("=")+1,a.lastIndexOf(")")),10)/100;b.vml.color.shape.style.filter=b.currentStyle.filter;b.vml.image.fill.opacity=a}},handlePseudoHover:function(a){setTimeout(function(){DD_belatedPNG.applyVML(a)},1)},fix:function(a){if(this.screenStyleSheet){var c,b;c=a.split(",");for(b=0;b<c.length;b++){this.screenStyleSheet.addRule(c[b],"behavior:expression(DD_belatedPNG.fixPng(this))")}}},applyVML:function(a){a.runtimeStyle.cssText="";this.vmlFill(a);this.vmlOffsets(a);this.vmlOpacity(a);if(a.isImg){this.copyImageBorders(a)}},attachHandlers:function(i){var d,c,g,e,b,f;d=this;c={resize:"vmlOffsets",move:"vmlOffsets"};if(i.nodeName=="A"){e={mouseleave:"handlePseudoHover",mouseenter:"handlePseudoHover",focus:"handlePseudoHover",blur:"handlePseudoHover"};for(b in e){if(e.hasOwnProperty(b)){c[b]=e[b]}}}for(f in c){if(c.hasOwnProperty(f)){g=function(){d[c[f]](i)};i.attachEvent("on"+f,g)}}i.attachEvent("onpropertychange",this.readPropertyChange)},giveLayout:function(a){a.style.zoom=1;if(a.currentStyle.position=="static"){a.style.position="relative"}},copyImageBorders:function(b){var c,a;c={borderStyle:true,borderWidth:true,borderColor:true};for(a in c){if(c.hasOwnProperty(a)){b.vml.color.shape.style[a]=b.currentStyle[a]}}},vmlFill:function(e){if(!e.currentStyle){return}else{var d,f,g,b,a,c;d=e.currentStyle}for(b in e.vml){if(e.vml.hasOwnProperty(b)){e.vml[b].shape.style.zIndex=d.zIndex}}e.runtimeStyle.backgroundColor="";e.runtimeStyle.backgroundImage="";f=true;if(d.backgroundImage!="none"||e.isImg){if(!e.isImg){e.vmlBg=d.backgroundImage;e.vmlBg=e.vmlBg.substr(5,e.vmlBg.lastIndexOf('")')-5)}else{e.vmlBg=e.src}g=this;if(!g.imgSize[e.vmlBg]){a=document.createElement("img");g.imgSize[e.vmlBg]=a;a.className=g.ns+"_sizeFinder";a.runtimeStyle.cssText="behavior:none; position:absolute; left:-10000px; top:-10000px; border:none; margin:0; padding:0;";c=function(){this.width=this.offsetWidth;this.height=this.offsetHeight;g.vmlOffsets(e)};a.attachEvent("onload",c);a.src=e.vmlBg;a.removeAttribute("width");a.removeAttribute("height");document.body.insertBefore(a,document.body.firstChild)}e.vml.image.fill.src=e.vmlBg;f=false}e.vml.image.fill.on=!f;e.vml.image.fill.color="none";e.vml.color.shape.style.backgroundColor=d.backgroundColor;e.runtimeStyle.backgroundImage="none";e.runtimeStyle.backgroundColor="transparent"},vmlOffsets:function(d){var h,n,a,e,g,m,f,l,j,i,k;h=d.currentStyle;n={W:d.clientWidth+1,H:d.clientHeight+1,w:this.imgSize[d.vmlBg].width,h:this.imgSize[d.vmlBg].height,L:d.offsetLeft,T:d.offsetTop,bLW:d.clientLeft,bTW:d.clientTop};a=(n.L+n.bLW==1)?1:0;e=function(b,p,q,c,s,u){b.coordsize=c+","+s;b.coordorigin=u+","+u;b.path="m0,0l"+c+",0l"+c+","+s+"l0,"+s+" xe";b.style.width=c+"px";b.style.height=s+"px";b.style.left=p+"px";b.style.top=q+"px"};e(d.vml.color.shape,(n.L+(d.isImg?0:n.bLW)),(n.T+(d.isImg?0:n.bTW)),(n.W-1),(n.H-1),0);e(d.vml.image.shape,(n.L+n.bLW),(n.T+n.bTW),(n.W),(n.H),1);g={X:0,Y:0};if(d.isImg){g.X=parseInt(h.paddingLeft,10)+1;g.Y=parseInt(h.paddingTop,10)+1}else{for(j in g){if(g.hasOwnProperty(j)){this.figurePercentage(g,n,j,h["backgroundPosition"+j])}}}d.vml.image.fill.position=(g.X/n.W)+","+(g.Y/n.H);m=h.backgroundRepeat;f={T:1,R:n.W+a,B:n.H,L:1+a};l={X:{b1:"L",b2:"R",d:"W"},Y:{b1:"T",b2:"B",d:"H"}};if(m!="repeat"||d.isImg){i={T:(g.Y),R:(g.X+n.w),B:(g.Y+n.h),L:(g.X)};if(m.search("repeat-")!=-1){k=m.split("repeat-")[1].toUpperCase();i[l[k].b1]=1;i[l[k].b2]=n[l[k].d]}if(i.B>n.H){i.B=n.H}d.vml.image.shape.style.clip="rect("+i.T+"px "+(i.R+a)+"px "+i.B+"px "+(i.L+a)+"px)"}else{d.vml.image.shape.style.clip="rect("+f.T+"px "+f.R+"px "+f.B+"px "+f.L+"px)"}},figurePercentage:function(d,c,f,a){var b,e;e=true;b=(f=="X");switch(a){case"left":case"top":d[f]=0;break;case"center":d[f]=0.5;break;case"right":case"bottom":d[f]=1;break;default:if(a.search("%")!=-1){d[f]=parseInt(a,10)/100}else{e=false}}d[f]=Math.ceil(e?((c[b?"W":"H"]*d[f])-(c[b?"w":"h"]*d[f])):parseInt(a,10));if(d[f]%2===0){d[f]++}return d[f]},fixPng:function(c){c.style.behavior="none";var g,b,f,a,d;if(c.nodeName=="BODY"||c.nodeName=="TD"||c.nodeName=="TR"){return}c.isImg=false;if(c.nodeName=="IMG"){if(c.src.toLowerCase().search(/.png$/)!=-1){c.isImg=true;c.style.visibility="hidden"}else{return}}else{if(c.currentStyle.backgroundImage.toLowerCase().search(".png")==-1){return}}g=DD_belatedPNG;c.vml={color:{},image:{}};b={shape:{},fill:{}};for(a in c.vml){if(c.vml.hasOwnProperty(a)){for(d in b){if(b.hasOwnProperty(d)){f=g.ns+":"+d;c.vml[a][d]=document.createElement(f)}}c.vml[a].shape.stroked=false;c.vml[a].shape.appendChild(c.vml[a].fill);c.parentNode.insertBefore(c.vml[a].shape,c)}}c.vml.image.shape.fillcolor="none";c.vml.image.fill.type="tile";c.vml.color.fill.on=false;g.attachHandlers(c);g.giveLayout(c);g.giveLayout(c.offsetParent);c.vmlInitiated=true;g.applyVML(c)}};try{document.execCommand("BackgroundImageCache",false,true)}catch(r){}DD_belatedPNG.createVmlNameSpace();DD_belatedPNG.createVmlStyleSheet();


// ie6 png 透明
DD_belatedPNG.fix(".png");

opacity透明：整个元素透明，包括元素里面的内容

<!-- html -->
<div class="opacity"><span style="color:yellow;">this is opacity text</span></div>

<div class="opacity"><span style="color:yellow;position:relative;">this is text that not opacity in ie</span></div>

.opacity {
    background: #000;
    filter:alpha(opacity=50);
    *zoom:1;   /* sometimes it is needed */
    opacity: 0.5;

    font-size: 38px;
    color:#fff;    
}

rgba透明：只对背景透明，内容不会受到影响

<!-- html -->
<div class="rgbaAlpha">red green blue and alpha</div>

/* css */
.rgbaAlpha {
    width:300px;
    height:auto;
    padding:50px;
    filter:progid:DXImageTransform.Microsoft.gradient(startcolorstr=#7F000000,endcolorstr=#7F000000);
    background: rgba(0, 0, 0, 0.5);

    font-size: 38px;
    color:#fff;
}

 ie6 border边框断线问题

<!--
    元素浮动后，父元素有时会出现边框断线的问题，并会引发position定位异常
    height:1%;
    zoom:1;
    可消除这个问题
-->
<div style="border:1px solid #f00;_height:1%;_zoom:1;">
    <div style="float:left;100px;height:100px;"></div>
    <div style="float:left;100px;height:100px;"></div>
    <div style="clear:both;"></div>
</div>

 清除浮动

/* 
 * _height:1%
 * 触发了ie6的layout布局，能解决很多奇怪的问题
 * 详细链接：http://adamghost.com/2008/12/ie-haslayout-%E8%AF%A6%E8%A7%A3/
*/
.clearfix{overflow:auto;_height:1%;}