<script>
function f1()
{
for(i=0;i<3;i++)
{
alert(i);
}
}
</script>
<body>
<input type=button value="sssss">
<form name=form1 ID=Form1>
<script> function tt(){document.all.Hidden1.value=1;}</script>
<select onchange=tt() ID=Select1>
<option>sdf</option>
<option>sss</option>
</select>
</form>
<form name=form2 ID=Form2><input type=hidden name=hid ID=Hidden1>
</form>
</body>
<input type=hidden name=hid ID=Hidden1>//加上id
<select onchange='tt();'>
<option selected>aaa</option>
<option>fff</option>
<option>eee</option>
</select>
</form>
<form name='form2'>
<input type='text' name='hid'>
</form>
<script>
function tt(){
document.form2.hid.value = 1;
}
</script>