效果：http://hovertree.com/texiao/jquery/43/
效果二：http://hovertree.com/texiao/jquery/43/1/
请在IE中体验。
1、创建JS文件：jquery.JPlaceholder.js
js代码如下：
/*
* jQuery placeholder, fix for IE6,7,8,9
* hovertree.com
*/
var JPlaceHolder = {
//检测
_check : function(){
return 'placeholder' in document.createElement('input');
},
//初始化
init : function(){
if(!this._check()){
this.fix();
}
},
//修复 何问起
fix : function(){
jQuery(':input[placeholder]').each(function(index, element) {
var self = $(this), txt = self.attr('placeholder');
self.wrap($('<div></div>').css({position:'relative', zoom:'1', border:'none', background:'none', padding:'none', margin:'none'}));
var pos = self.position(), h = self.outerHeight(true), paddingleft = self.css('padding-left');
var holder = $('<span></span>').text(txt).css({position:'absolute', left:pos.left, top:pos.top, height:h, lienHeight:h, paddingLeft:paddingleft, color:'#aaa'}).appendTo(self.parent());
self.focusin(function(e) {
holder.hide();
}).focusout(function(e) {
if(!self.val()){
holder.show();
}
});
holder.click(function(e) {
holder.hide();
self.focus();
});
});
}
};
//执行
jQuery(function(){
JPlaceHolder.init();
});
2、页面中使用方法如下：
<!doctype html>
<html>
<head>
<meta charset="utf-8">
<title>jQuery JPlaceholder Demo - 何问起</title>
<script src="http://hovertree.com/ziyuan/jquery/jquery-1.8.3.min.js"></script>
<script src="http://hovertree.com/texiao/jquery/43/jquery.JPlaceholder.js"></script>
</head> <body>
<form>
<div>
<ul>
<li>
<input type="text" name="username" placeholder="用户名">
</li>
<li>
<input type="password" name="username" placeholder="密码">
</li>
<li>
<button type="button">登录</button>
</li>
</ul>
</div>
</form>
<a href="http://hovertree.com/h/bjaf/ww7ek8wn.htm">参考</a>
</body>
</html>