<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<HTML>
<SCRIPT LANGUAGE="JavaScript">
function check()
{
var m;
var str = document.all("start").value;
var options = document.all("end").options;
alert(options.length);
for(var i=0;i<options.length;i++)
{
options.remove(0);
}
for (m=str;m<=3;m++)
{
var month=document.createElement("option");
month.text=m;
document.frm.end.add(month);
}}
</script>
<BODY>
<select name="start" onchange="check()">
<option value="0" selected>0</option>
<option value="1">1</option>
<option value="2">2</option>
<option value="3">3</option>
</select>
<select name="end">
<option value="0">0</option>
<option value="1">1</option>
<option value="2">2</option>
<option value="3" selected>3</option>
</select>
</BODY>
</HTML>
<HTML>
<SCRIPT LANGUAGE="JavaScript">
function check()
{
var m;
var str = document.all("start").value;
var options = document.all("end").options;
alert(options.length);
for(var i=0;i<options.length;i++)
{
options.remove(0);
}
for (m=str;m<=3;m++)
{
var month=document.createElement("option");
month.text=m;
document.frm.end.add(month);
}}
</script>
<BODY>
<select name="start" onchange="check()">
<option value="0" selected>0</option>
<option value="1">1</option>
<option value="2">2</option>
<option value="3">3</option>
</select>
<select name="end">
<option value="0">0</option>
<option value="1">1</option>
<option value="2">2</option>
<option value="3" selected>3</option>
</select>
</BODY>
</HTML>
document找不到 frm这个东东