<!--隔行变色的表格-->
window.onload=function showtable(){
var tablename=document.getElementById("mytable");
var li=tablename.getElementsByTagName("tr");
for (var i=0;i<=li.length;i++){
    if (i%2==0){
      li[i].style.backgroundColor="#E1F1F1";
    }else li[i].style.backgroundColor="#F0F0F0";
}
}