asp实现转到第几页（2）

<form id="pageForm" name="pageForm" method="post">
<input name="pageNumber" type="text" id="pageNumber" size="8" onkeydown="if(event.keyCode == 13) pageReturn();"/>
<input name="btnReturn" type="button" id="btnReturn" value="转到" onclick="pageReturn();"/>
</form>
<script language="javascript">
function pageReturn() {
if (pageForm.pageNumber.value == "") {
alert("请输入页号");
return;
}
window.open("index.asp?page=" + pageForm.pageNumber.value, "_self") ;
}
</script>