制作一个可以实施浏览图片的上传图片功能

<SCRIPT language=JavaScript>
var flag=false;
function DrawImage(ImgD){
   var image=new Image();
   image.src=ImgD.src;
   if(image.width>0 && image.height>0){
    flag=true;
    if(image.width/image.height>= 120/80){
     if(image.width>120){
     ImgD.width=120;
     ImgD.height=(image.height*120)/image.width;
     }else{
     ImgD.width=image.width;
     ImgD.height=image.height;
     }
     ImgD.alt=image.width+"×"+image.height;
     }
    else{
     if(image.height>80){
     ImgD.height=80;
     ImgD.width=(image.width*80)/image.height;
     }else{
     ImgD.width=image.width;
     ImgD.height=image.height;
     }
     ImgD.alt=image.width+"×"+image.height;
     }
    }
   /*else{
    ImgD.src="";
    ImgD.alt=""
    }*/
   }
function FileChange(Value){
flag=false;
document.all.uploadimage.width=10;
document.all.uploadimage.height=10;
document.all.uploadimage.alt="";
document.all.uploadimage.src=Value;
}
function BeforeUpLoad(){
if(flag) alert("OK");else alert("FAIL");
}
</SCRIPT>
<INPUT style="WIDTH: 143px; HEIGHT: 18px" type=file onchange=javascript:FileChange(this.value); size=8 name=pic> <IMG id=uploadimage height=10 src="" width=10 onload=javascript:DrawImage(this);><BR><BUTTON onclick=javascript:BeforeUpLoad();>提交</BUTTON></P>