让IE支持placeholder属性
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 = $(this), txt = self.attr('placeholder'); // 如果当前输入框中有值,不做处理 if (self.val() != '') { // jquery each方法,return true = continue; return false = break; return true; } self.wrap($('<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:'5px', 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>