[Deff]

<script>
window.onload=function(){
    document.getElementById("div").onclick  = function(){ alert('div'); };
}
</script>
<div id="div" style="border:1px solid blue; color:red; font-weight:700; cursor:pointer">div</div>

<script>
function Clk(a){ 
    alert('div'); 
};
</script>

<div id="div"  onclick="Clk(this)" style="border:1px solid blue; color:red; font-weight:700; cursor:pointer">div</div>