纯css简单的警告框加抖动效果

这种效果的警告框，出错了会抖动

.alert-box {
          width: 400px;
          border-style: outset;
          position: relative;
          color:#555;
          border-radius:10px;
          font-family:Tahoma,Geneva,Arial,sans-serif;font-size:11px;
          padding:10px 10px 10px 10px;
          margin:auto;
          display: none;
      }

      .alert-box span {
          font-weight:bold;
          text-transform:uppercase;
      }

      .error {
          background:#ffecec no-repeat 10px 50%;
          border:1px solid #f5aca6;
      }

jQuery的动画效果，animate for循环4次左右移动

var $box = $(‘.alert-box‘);
                  $box.html(‘<span>error: </span>‘ + data.error);
                  $box.show();
                  var box_left = ($(window).width() -  $box.width()) / 2;
                  for(var i=1; 4>=i; i++){
                      $box.animate({left:-(40-10*i)},50);
                      $box.animate({left:+2*(40-10*i)},50);
                  }