可以通过索引.<select name="sel">
<option value="111">111
<option value="aaa">aaa
<option value="bbb">bbb
</select>
<script>
document.all.sel.options[1].selected = true;
</script>
<option value="111">111
<option value="aaa">aaa
<option value="bbb">bbb
</select>
<script>
document.all.sel.options[1].selected = true;
</script>
<select name="sel">
<option value="111">111
<option value="aaa">aaa
<option value="bbb">bbb
</select>
<script>
var sel = document.all.sel;
for(var i=0;i<sel.options.length;i++)
{
if(sel.options[i].value == "aaa")
{
sel.options[i].selected = true;
}
}
</script>
<select name="sel">
<option value="111">111
<option value="aaa">aaa
<option value="bbb">bbb
</select>
<script>
var sel = document.all.sel;
for(var i=0;i<sel.options.length;i++)
{
if(sel.options[i].text== "aaa")
{
sel.options[i].selected = true;
}
}
</script>