function pictChange(){topImg=Math.floor(Math.random()*4+1);if(document.all){document.all("bgChnage").style.background="#e5e5e5 url('../common/image/bg"+topImg+".gif') repeat center top fixed";}else if(navigator.userAgent.indexOf("Gecko")!=-1){document.getElementById("bgChnage").style.background="#e5e5e5 url('../common/image/bg"+topImg+".gif') repeat center top fixed";}}