<span id=span1>
<input name=ab type=file>
</span>
<input name=button1 type=button value="按" onclick=show()>
<script language=javascript>
function show()
{
document.getElementById("span1").innerHTML="<input name=ab type=file>";
}
</script>
<input name=ab type=file>
</span>
<input name=button1 type=button value="按" onclick=show()>
<script language=javascript>
function show()
{
document.getElementById("span1").innerHTML="<input name=ab type=file>";
}
</script>
http://community.csdn.net//Expert/TopicView2.asp?id=4360247&datebasetype=now
js FAQ贴
http://community.csdn.net//Expert/TopicView2.asp?id=4356360&datebasetype=now
DHTML手册,js手册,dom手册下载
http://community.csdn.net//Expert/TopicView2.asp?id=4356325&datebasetype=now
<input name=button1 type=button value="按" onclick=show()>
<script language=javascript>
function show()
{
document.getElementById("ab").outerHTML="<input name=ab type=file>";
}
</script>