var browserSupport = {placeholder: 'placeholder' in document.createElement('input')
}$(function() {//模拟placeholderif( !browserSupport.placeholder){$('input[placeholder],textarea[placeholder]').each(function(){var that = $(this),text= that.attr('placeholder'),oldType; if(that.val()===""){that.val(text).addClass('placeholder');                }   that.focus(function(){//ie8下readonly依然可以上焦点的处理if(that.attr('readonly')){that.blur();return;}that.removeClass('placeholder');if(that.val()===text){   that.val("");   }   }).blur(function(){if(that.val()===""){ that.val(text).addClass('placeholder');//防止异常情况：当有placeholder类，且值不为空（代码设置值时容易出现）}else{that.removeClass('placeholder');}   }).closest('form').submit(function(){   if(that.val() === text){   that.val('');   }   });   });}
});    

/*
.placeholder{    color: #aaa!important;
}
span.placeholder{position: absolute;left: 0;line-height: 34px;padding-left: 12px;
}
*/
var browserSupport = {placeholder: 'placeholder' in document.createElement('input')
}/* ajax请求发现未登录时，服务端返回401错误，然后此处统一处理401错误，跳转到登录页面 */
$(document).ready(function() {//模拟placeholderif( !browserSupport.placeholder){$('input[placeholder],textarea[placeholder]').each(function(){var that = $(this),text= that.attr('placeholder'),oldType; if(that.val()===""){if(that.attr('type') != 'password'){that.val(text).addClass('placeholder');  }else{that.before('<span class="placeholder">请输入密码</span>');}}   that.focus(function(){//ie8下readonly依然可以上焦点的处理if(that.attr('readonly')){that.blur();return;}//清除span.placeholderthat.prev("span.placeholder").remove();that.removeClass('placeholder');if(that.val()===text){   that.val("");   }   }).blur(function(){if(that.val()===""){if(that.attr('type') != 'password'){   that.val(text).addClass('placeholder');}else{that.before('<span class="placeholder">请输入密码</span>');}//防止异常情况：当有placeholder类，且值不为空（代码设置值时容易出现）}else{that.removeClass('placeholder');}   }).closest('form').submit(function(){   if(that.val() === text){   that.val('');   }   });   }); $(document).on('click','span.placeholder',function(){$(this).next("[placeholder]").focus();//删除span.placeholder会在[placeholder]的focus中进行
        })}
})