如何给按扭加超链接？？？？？？？？？？？？？

1<input class="ntbar" type="button" value="上一页"/>

1<input class="ntbar" onclick="window.location=aa.htm" type="button" value="上一页"/>

1<script language="JavaScript">   
2function click_btn()   
3{   
4window.parent.location="your_file.asp";   
5}   
6</script>

1<input class="ntbar" oncilck="JavaScript:click_btn();" style="cursor:hand" type="button" value="上一页"/>

1<input class="ntbar" onclick="JavaScript:window.history.go(-1);" style="cursor:hand" type="button" value="上一页"/>