表示要素の場所を取得する

<script type="text/javascript">
function test1(layName){
	var top    = document.getElementById(layName).offsetTop;
	var left   = document.getElementById(layName).offsetLeft;
	var height = document.getElementById(layName).offsetHeight;
	var width  = document.getElementById(layName).offsetWidth;
	alert('トップ：' + top + '　レフト：' + left + '　高さ：' + height + '　幅：' + width )

document.getElementById('help2').style.top = height + 100;
document.getElementById('help2').style.left = left;
}
</script>
</head>
<h1>要素の場所とサイズ</h1>

<a href="Javascript:test1('help1');">テスト</a>
<div id="help1">ヘルプ1</div>
<div id="help2">ヘルプ2</div>