<select id=a1 multiple>
<option value=1>a
<option value=2>b
<option value=3>c
<option value=4>d
</select>
<script>
function go(){
var s=[];
for(i=0;i<a1.length;i++)if(a1[i].selected)s[s.length]=a1[i].value;
s!=""?alert(s):null;
}
</script>
<input type=button onclick=go()>
<option value=1>a
<option value=2>b
<option value=3>c
<option value=4>d
</select>
<script>
function go(){
var s=[];
for(i=0;i<a1.length;i++)if(a1[i].selected)s[s.length]=a1[i].value;
s!=""?alert(s):null;
}
</script>
<input type=button onclick=go()>
<input type=checkbox name=abc value=bb><br>
<input type=checkbox name=abc value=cc><br>
<input type=checkbox name=abc value=dd><br>
<input type=checkbox name=abc value=ee><br>
<input type=checkbox name=abc value=ff><br>
<input type=button value=check onclick=cc()><script language=javascript>
function cc()
{
var a = document.getElementsByName("abc");
var m = "";
for (var i=0; i<a.length; i++)
{
if (a[i].checked){alert(a[i].value); m = "a"; }
}
if (m == "") alert("你一个都没有选中.");
}
</script>