SO - 16917020

by Arun P Johny

HTML

<div id="pos"></div>
<div id="drag" style="width:2000px;height:2000px;border:1px solid #000; top:100px; left:100px; position:absolute; background-color: #AACCEE">
    
</div>

JavaScript

document.getElementById('drag').onmouseup = function(event){
    var event = event || window.event;
    var x = event.pageX - this.offsetLeft;
    var y = event.pageY - this.offsetTop;         
    document.getElementById('pos').innerHTML = x + ', ' + y;
}