I'm trying to change the CSS of a div that looks like a line so that the line appears to move down the screen. I'm getting no response as yet, just the div and button on screen. This script is in the head:

Code:
<script type="text/javascript">	
function moves() {
	if (tops < 500) {
	var tops = tops + 1;
	document.getElementById('line1').style.top = tops;
	setTimeout(moves,20);
	}
}

function move() {
	var tops = 4;
	moves();
	}	
</script>
and this is my code in the body:

Code:
<input type="button" onclick="move()" value="Line do">
<div id="line1" class="line horizontal" style="top: 4px; width: 100%; height: 1px;"></div>

Please help!