原文：https://www.oschina.net/code/snippet_206691_26471#44160
让支持的直接路过，不支持的，完美显示~~
/* * jQuery placeholder, fix for IE6,7,8,9 * @author JENA * @since 20131115.1504 * @website ishere.cn */var JPlaceHolder = { //检测 _check : function(){ return ‘placeholder‘ in document.createElement(‘input‘); }, //初始化 init : function(){ if(!this._check()){ this.fix(); } }, //修复 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(); });<!doctype html><html><head><meta charset="utf-8"><title>jQuery JPlaceholder Demo</title><script src="jquery-1.8.3.min.js"></script><script src="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></body></html>原文：http://www.cnblogs.com/runerering/p/6218037.html