I wrote this code which should add all the numbers that are dividable by 3 or 5 below 1000, however I can't get to print the answer on the screen.

Code:
<html>
<head>
	<title>Problem 1 project euler</title>
</head>
<body>
	<script>
	var x = 0
	var _tel = 0
	while (_tel <= 1000)
	{
		if (((_tel/3)) = ((math.round((_tel/3))))
			{
			var x = x + _tel;
			}
		else if (((_tel/5)) = ((math.round((_tel/5))))
			{
			var x = x + _tel;
			}
		else
			{
			}
		var _tel = _tel + 1
	}
	document.write (x)
	</script>
</body>
</html>
I hope anyone can tell me why it doesnt work.

Appel