Snap an element to the mouse

gistfile1.js

<script>
    var mouseIsDown = false;
    
    function init() {
        document.onmousedown = function(e) {
            mouseIsDown = true;
        };
        
        document.onmouseup = function(e) {
            mouseIsDown = false;
        };
        
        document.onmousemove = function(e) {
            var toPickUp = document.getElementById('draggable00');
            
            if (mouseIsDown) {
                snapToMouse(toPickUp);
                toPickUp.style['background-color'] = '#FF0000';
            } else {
                toPickUp.style['background-color'] = '#000000';
            }
        };
    }
    
    function snapToMouse(obj) {
        obj.style['left'] = window.event.clientX+'px';
        obj.style['top'] = window.event.clientY+'px';
    }
    
</script>