ie6下如果用css圖片平鋪，會出現cpu短暫100%的情況，主要原因在于，ie6會重復下載圖片。
 

//代碼如下:document.execCommand("BackgroundImageCache", false, true); //當然為了其它瀏覽器上能正常通過，需要做下判斷后調用，才更安全： //復制代碼 代碼如下:if(Browser.isIE6){ try{ document.execCommand("BackgroundImageCache", false, true); } catch(e1){} } //平臺檢測代碼可以這樣寫，摘自Ext源碼： //代碼如下: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 //代碼如下:function extend(obj1,obj2){ for(var o in obj2){ obj1[o] = obj2[o]; } return obj1; } 詳細出處參考：http://www.jb51.net/article/25575.htm