不知道你说的是这个不?
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<HTML>
<HEAD>
<TITLE> New Document </TITLE>
<META NAME="Generator" CONTENT="EditPlus">
<META NAME="Author" CONTENT="">
<META NAME="Keywords" CONTENT="">
<META NAME="Description" CONTENT="">
<script>
function set(obj){
var s = document.getElementById('t');
if(obj.value=='y'){
s.disabled=false;
}else{
s.disabled=true;
}
}
</script>
</HEAD> <BODY>
<select onchange='set(this)'>
<option value='y'>Yes</option>
<option value='n'>no</option>
</select> <select id=t>
<option value='ay'>aaa</option>
<option value='bn'>bbb</option>
</select>
</BODY>
</HTML>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<HTML>
<HEAD>
<TITLE> New Document </TITLE>
<META NAME="Generator" CONTENT="EditPlus">
<META NAME="Author" CONTENT="">
<META NAME="Keywords" CONTENT="">
<META NAME="Description" CONTENT="">
<script>
function set(obj){
var s = document.getElementById('t');
if(obj.value=='y'){
s.disabled=false;
}else{
s.disabled=true;
}
}
</script>
</HEAD> <BODY>
<select onchange='set(this)'>
<option value='y'>Yes</option>
<option value='n'>no</option>
</select> <select id=t>
<option value='ay'>aaa</option>
<option value='bn'>bbb</option>
</select>
</BODY>
</HTML>
解决方案 »
免费领取超大流量手机卡,每月29元包185G流量+100分钟通话, 中国电信官方发货