當你瀏覽一些Blog時，會看到在留言框、搜尋欄或者Email訂閱欄中有一段預設的文本，比如“Type your comment here”，如果你在其中點擊（表單擷取焦點），這段預設的文本就會自動消失。實現這種效果非常簡單：
1．在Header.php中添加如下指令碼：
<head>
....
//指令碼要放在head標籤裡面
<script type="text/javascript">
function clearDefault(el) {
if (el.defaultValue==el.value) el.value = ""
}
</script>
...
</head>
2．如果是輸入欄（Input），在其中添加一個onfocus參數，如：
<input type="text" id="input_email_address" name="email" class="input" value="Your Email Address"
onfocus="clearDefault(this)" />
3．如果是文本域，添加的onfocus參數如下：
<textarea name="comment" id="input_comment" rows="10" class="input textarea"
onfocus="this.value=''; this.onfocus=null;" >Type your comment here</textarea>
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