通過設置display屬性可以使div隱藏後釋放佔用的頁面空間，如下
style = "display: none;"
document.getElementById("t2").style.display = "none"; //隱藏
document.getElementById("t2").style.display = "block"; //顯示
參考實例代碼：
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="X-UA-Compatible" content="IE=7"/>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>visibility與display的差別</title>
</head>
<script type="text/javascript">
function $(id){ return id?document.getElementById(id):''; }
</script>
<body>
<div id="s1" style="width:200px; height:200px; background-color:#f00; float:left;">這是一個顯示層,使用display顯示與隱藏！</div>
<div id="s2" style="width:200px; height:200px; background-color:#Aff;float:left;">這是一個顯示層,使用visibility顯示與隱藏！</div>
<br/><br/>
<input type="button" οnclick="$('s1').style.display = 'none';" value="display隱藏層" /><br/>
<input type="button" οnclick="$('s1').style.display = 'block';" value="display顯示層" /><br/>
<input type="button" οnclick="$('s2').style.visibility = 'hidden';" value="visibility隱藏層" /><br/>
<input type="button" οnclick="$('s2').style.visibility = 'visible';" value="visibility顯示層" />
</body>
</html>