<script language="JavaScript"> <!-- //图片按比例缩放 var flag=false; function DrawImage(ImgD,iwidth,iheight){     //参数(图片,允许的宽度,允许的高度)     var image=new Image();     image.src=ImgD.src;     if(image.width>0 && image.height>0){     flag=true;     if(image.width/image.height>= iwidth/iheight){         if(image.width>iwidth){           ImgD.width=iwidth;         ImgD.height=(image.height*iwidth)/image.width;         }else{         ImgD.width=image.width;           ImgD.height=image.height;         }         ImgD.alt=image.width+"×"+image.height;         }     else{         if(image.height>iheight){           ImgD.height=iheight;         ImgD.width=(image.width*iheight)/image.height;                 }else{         ImgD.width=image.width;           ImgD.height=image.height;         }         ImgD.alt=image.width+"×"+image.height;         }     } }  //--> </script> 调用：<img src="images/toplogo.gif" onload="javascript:DrawImage(this,100,100)">