.net d_file.myform.uploadfile 为空或不是对象

修改方案：document.write('<iframe id=d_file frameborder=0 src="../upload/?flag=img" width="100%" height="22" scrolling=no

></iframe>');
换成
document.write('<iframe id=d_file frameborder=0 src="../upload/Default.aspx?flag=img" width="100%" height="22"

scrolling=no ></iframe>');