IE6下CSS图片缓存问题解决方法

ie6下如果用css图片平铺，会出现cpu短暂100%的情况，主要原因在于，ie6会重复下载图片。
 

//代码如下:document.execCommand("BackgroundImageCache", false, true); //当然为了其它浏览器上能正常通过，需要做下判断后调用，才更安全： //复制代码 代码如下:if(Browser.isIE6){ try{ document.execCommand("BackgroundImageCache", false, true); } catch(e1){} } //平台检测代码可以这样写，摘自Ext源码： //代码如下:var Browser = {}; try{ (function(){ var idSeed = 0, ua = navigator.userAgent.toLowerCase(), check = function(r){ return r.test(ua); }, DOC = document, isStrict = DOC.compatMode == "CSS1Compat", isOpera = check(/opera/), isChrome = check(//bchrome/b/), isWebKit = check(/webkit/), isSafari = !isChrome && check(/safari/), isSafari2 = isSafari && check(/applewebkit//4/), // unique to Safari 2 isSafari3 = isSafari && check(/version//3/), isSafari4 = isSafari && check(/version//4/), isIE = !isOpera && check(/msie/), isIE7 = isIE && check(/msie 7/), isIE8 = isIE && check(/msie 8/), isIE6 = isIE && !isIE7 && !isIE8, isGecko = !isWebKit && check(/gecko/), isGecko2 = isGecko && check(/rv:1/.8/), isGecko3 = isGecko && check(/rv:1/.9/), isBorderBox = isIE && !isStrict, isWindows = check(/windows|win32/), isMac = check(/macintosh|mac os x/), isAir = check(/adobeair/), isLinux = check(/linux/), isIpad = check(/ipad/), isSecure = /^https/i.test(window.location.protocol); extend(Browser,{ isOpera:isOpera, isIE:isIE, isIE6:isIE6, isFirefox:isGecko, isSafari:isSafari, isChrome:isChrome, isIpad:isIpad }); })(); }catch(e){} //上面extend方法也很easy //代码如下:function extend(obj1,obj2){ for(var o in obj2){ obj1[o] = obj2[o]; } return obj1; } 详细出处参考：http://www.jb51.net/article/25575.htm