[bes]

<style>
 div {
   position: absolute;
   left: 0px;
   top: 0px;
   width: 100px;
   height: 100px;
   background: green;
 }
</style>

<div id="div1">
	div1  
</div>
<div id="div2">
	div2
</div>

<script>
window.onload = function () {
	var div1 = document.getElementById('div1');
	var div2 = document.getElementById('div2');
	div1.onclick = function () {
		alert('div1');
	}
	div2.onclick = function () {
		div1.click();
	}
}
</script>