IE下png图形的另一种处理方法

IE下png图形的另一种处理方法(3)     // this is an attempt to set the image to itself!
    // pointless - leave the filter as-is, restore the blank image
    element.src = blankSrc;
  } else {
    // set the image to something different
    if (IS_PNG.test(element.src)) {
      // fixable PNG
      realSrc = element.src;
      element.src = blankSrc;
      element.runtimeStyle.filter = "progid:DXImageTransform.Microsoft.AlphaImageLoader(src='" + realSrc + "',sizingMethod='scale')";
    } else {
      // ordinary image - make sure the fix is removed
      if (realSrc) {
        realSrc = null;
        element.runtimeStyle.filter = '';
      }
    }
  }
}
function beforePrint() {
  if (realSrc) {
    supported = false;
    element.src = realSrc;
    element.runtimeStyle.filter = '';
    supported = true;
  }
}
function afterPrint() {
  if (realSrc) {
    var rs = realSrc;
    realSrc = null;
    element.src = rs;
  }
}
</script>
</public:component>

注意：该种方法须指定 width, height

IE 7+就不用这些麻烦了