JS限定手机版中图片大小随分辨率自动调整

<script type="text/javascript">
      var ObjImg = jQuery(".Dy_Content img");
      for (var i = 0; i < ObjImg.length; i++) {

          loadImage(ObjImg.eq(i));
      }
      function loadImage(Obj) {
          var b_width = 320;
          var img = new Image();
          img.src = jQuery(Obj).attr("src");
          if (img.complete) {
              var i_width = img.width;
              var i_height = img.height;
              if (i_width > b_width) {
                  var bx = b_width / i_width;
                  jQuery(Obj).width(b_width);
                  jQuery(Obj).height((bx * i_height).toFixed(0));
              }
              return;
          }
          img.onload = function () {
              var i_width = this.width;
              var i_height = this.height;
              if (i_width > b_width) {
                  var bx = b_width / i_width;
                  jQuery(Obj).width(b_width);
                  jQuery(Obj).height((bx * i_height).toFixed(0));
              }
          };
      }; 
</script>