拦截表单的另外一种写法

<script language="vbs">
sub send_onclick           
dim f
set f=document.ff
photo=trim(f.photo.value)        
if photo="" then        
msgbox "没有照片，怎么传！       ",64 ,"上传"       
f.photo.focus      
exit sub      
end if        
f.submit      
end sub               
sub retu_onclick
    history.back
end sub
</script>

<form method=POST action=saveedit.asp name=ff enctype=multipart/form-data>
<input type=file name=photo>
<input type=button value=开始上传 name=send>
</form>