placeholder在IE8中兼容性问题解决

<script type="text/javascript">     if( !('placeholder' in document.createElement('input')) ){       $('input[placeholder],textarea[placeholder]').each(function(){          var that = $(this),          text= that.attr('placeholder');          if(that.val()===""){            that.val(text).addClass('placeholder');          }          that.focus(function(){            if(that.val()===text){              that.val("").removeClass('placeholder');            }          })          .blur(function(){            if(that.val()===""){              that.val(text).addClass('placeholder');            }          })          .closest('form').submit(function(){            if(that.val() === text){              that.val('');            }          });        });      }   </script>