<script language="javascript">
function test()
{
//alert(document.getElementById("b").disabled);
if(document.getElementById("a").value!="3")
{
var objSelect = document.getElementById("b");
for (var i = 0; i < objSelect.options.length; i++) {
if (objSelect.options[i].value == "3") {
objSelect.options[i].selected = true;
break;
}
}
document.getElementById("b").disabled=true;
}else
{
document.getElementById("b").disabled=false;
}
}
</script><select name="a" id="a" onchange="test()">
<option value="1">1</option>
<option value="2">2</option>
<option value="3">3</option>
</select>
<br />
<select name="b" id="b" disabled="disabled">
<option value="1">1</option>
<option value="2">2</option>
<option value="3" selected>3</option>
</select>
<HTML>
<HEAD>
<TITLE> New Document </TITLE>
<meta http-equiv="Content-Type" content="text/html; charset=gb2312" />
<META NAME="Generator" CONTENT="EditPlus">
<META NAME="Author" CONTENT="zourinet">
<META NAME="Keywords" CONTENT="">
<META NAME="Description" CONTENT="">
<script language="JavaScript">
/* <![CDATA[ */
function CheckSelected(obj,setSel)
{
if(obj.selectedIndex==2)
{
select2 = document.getElementById(setSel);
select2.disabled=true;
select2.selectedIndex=2; }
}
/* ]]> */
</script>
</HEAD><BODY>
<form method="post" action="">
<div>
<select name="select1" onchange="CheckSelected(this,'select2');">
<option value="1">1</option>
<option value="2">2</option>
<option value="3">3</option>
</select>
<select name="select2">
<option value="11">11</option>
<option value="22">22</option>
<option value="33">33</option>
</select>
</div>
</form>
</BODY>
</HTML>