JavaScript动态修改表单Action值的两种实现方式

<form id="form1" name="form1" method="post" action="../news/index.asp">
   <table width="100%" height="43" border="0" cellpadding="0" cellspacing="0">
    <tr>
     <td height="28"><input name="keyword" type="text" style="width:150px" id="keyword"/></td>
    </tr>
    <tr>
     <td height="28"><select name="Searchtype" style="width:110px" id="Searchtype" onchange="Searchtype1();">
      <option value="news" selected="selected">新闻中心</option>
      <option value="case">工程案例</option>
     </select>
     <input type="submit" name="Submit" value="搜索" /></td>
    </tr>
   </table>
 </form>
 <script language="javascript">
 function Searchtype1(){
 var type=document.getElementById("Searchtype").options[document.getElementById("Searchtype").selectedIndex].value;
 if (type=="news"){document.getElementById("form1").action="../news/index.asp"}
 else if (type=="case"){document.getElementById("form1").action="../case/index.asp"}
 }
 </script>

<html>
<head>
<script language="javascript">
function check(){
if(document.form1.a[0].checked==true)
document.form1.action="1.htm"
else
document.form1.action="2.htm"
}
</script>
</head>
<body>
<form name="form1" method="post" action="" onSubmit="check();">
转到页面一<input type="radio" name="a">
转到页面二<input type="radio" name="a">
<input name="" type="submit" value="提交">
</form>
</body>
</html>