JS创建缩略图

<script  language="javascript">
//显示缩略图
function DrawImage(ImgD,width_s,height_s){
 /*var width_s=139;
 var height_s=104;
 */
 var image=new Image();
 image.src=ImgD.src;
 if(image.width> && image.height>){
 flag=true;
 if(image.width/image.height>=width_s/height_s){
 if(image.width>width_s){
 ImgD.width=width_s;
 ImgD.height=(image.height*width_s)/image.width;
 }else{
 ImgD.width=image.width;
 ImgD.height=image.height;
 }
 }
 else{
 if(image.height>height_s){
 ImgD.height=height_s;
 ImgD.width=(image.width*height_s)/image.height;
 }else{
 ImgD.width=image.width;
 ImgD.height=image.height;
 }
 }
 }
 /*else{
 ImgD.src="";
 ImgD.alt=""
 }*/
 }
 </script>

调用
<div><img src="图片" align="center" onload="DrawImage(this,200,200)"></div>