用javascript取控件位置的方法
var divx;
var divy;
var e;
var y;
e=document.getElementById(id);
divx=e.offsetLeft;
divy=e.offsetTop;
y=e.offsetHeight;
while(e=e.offsetParent){
divy+=e.offsetTop;
divx+=e.offsetLeft;
}
divy=divy+y;