<SELECT name="yufa[]" onchange="hide(0)">
<option>1
<option>2
</SELECT>
<SELECT name="yufa[]" onchange="hide(1)">
<option>1
<option>2
</SELECT>
<SELECT name="yufa[]" onchange="hide(2)">
<option>1
<option>2
</SELECT>
<SCRIPT LANGUAGE="JavaScript">
<!--
function hide(idx){
var sellst = document.all("yufa[]");
for(var i=0;i<sellst.length;i++){
if (idx != i){
sellst[i].disabled=true;
}
}
}
//-->
</SCRIPT>
<option>1
<option>2
</SELECT>
<SELECT name="yufa[]" onchange="hide(1)">
<option>1
<option>2
</SELECT>
<SELECT name="yufa[]" onchange="hide(2)">
<option>1
<option>2
</SELECT>
<SCRIPT LANGUAGE="JavaScript">
<!--
function hide(idx){
var sellst = document.all("yufa[]");
for(var i=0;i<sellst.length;i++){
if (idx != i){
sellst[i].disabled=true;
}
}
}
//-->
</SCRIPT>
function proDis(i)
{
if (i==0)
{
document.all.ufa2.style.display="none";
document.all.ufa3.style.display="none";
}
else if(i==1)
{
document.all.ufa1.style.display="none";
document.all.ufa3.style.display="none";
}
else if(i==2)
{
document.all.ufa1.style.display="none";
document.all.ufa2.style.display="none";
}
}
</script><body>
<select name="ufa1" onclick="proDis(0)">
<option value="1">1</option>
<option value="2" selected>2</option>
</select>
<select name="ufa2" onclick="proDis(1)">
<option value="1">1</option>
<option value="2" selected>2</option>
</select>
<select name="ufa3" onclick="proDis(2)">
<option value="1">1</option>
<option value="2" selected>2</option>
</select></body>