请帮忙去掉个select

Question

<div class="seBox">
<form action="search.asp" id="qf" onsubmit="return doS()">
<select name="cat" id="catSelect">
<option value="">全部</option>
</select>
<input id="q" name="searchword" type="text" value="关键字" class="yuan" onfocus="if(this.value=='')this.value=''"/>
<img src="/search.gif"align="absmiddle" style="cursor:pointer" class="yuan" onclick="if(doS())document.getElementById('qf').submit()" />
</form>
</div>
<script type="text/javascript">
document.getElementById('catSelect').value='';
var q = document.getElementById('q');
function doS(){if(q.value==''){alert('请输入关键词!');q.focus();return false}return true}
</script>代码如上，这样搜索出来格式为/search.asp?cat=&searchword=关键字，我想变成搜索格式为/search.asp?searchword=关键字，也就是去掉cat=&。所以我想删除代码
<select name="cat" id="catSelect">
<option value="">全部</option>
</select>
但是删除代码之后点搜索没反应了，请帮忙修改下

Answer 1

改为：<div class="seBox"> <form action="search.asp" id="qf" onsubmit="return doS()">  <input id="q" name="searchword" type="text" value="关键字" class="yuan" onfocus="if(this.value=='')this.value=''"/> <img src="/search.gif"align="absmiddle" style="cursor:pointer" class="yuan" onclick="if(doS())document.getElementById('qf').submit()" /> </form> </div> 
<script type="text/javascript"> 
 var q = document.getElementById('q'); function doS(){if(q.value==''){alert('请输入关键词!');q.focus();return false}return true} 
</script> 

Answer 2

楼主把id为catSelect的Dom元素删了但是js中仍然：document.getElementById('catSelect').value=''; 可能问题出在这

Answer 3

document.getElementById('catSelect').value='';这句也去掉