<script language=javascript>
function preloadImages(){
  if(document.images){
        if(!document.MM_p) document.MM_p=new Array();
        var i, j=document.MM_p.length;
        for(i=0; i<arguments.length; i++){
            if (arguments[i].indexOf("#")!=0){
                document.MM_p[j]=new Image;
                document.MM_p[j++].src=arguments[i];
            }
        }
    }
}
</script>

应用：
 程序代码
<script language=javascript>
preloadImages("http://www.jzxue.com/images/logo.gif");
</script>