javascript和php是不同的,他们不能混用可改成如下形式:
<form action="xx.php" name="myform">
<select name="myselect" onchange="javascript:selectb()>
<option value='myparam1'>param1</option>
<option value='myparam2'>param2</option>
</select>
</form>
<script language="JavaScript" type="text/JavaScript"> function selectb()
{
alert(document.myform.myselect.value);
}
</script>
<form action="xx.php" name="myform">
<select name="myselect" onchange="javascript:selectb()>
<option value='myparam1'>param1</option>
<option value='myparam2'>param2</option>
</select>
</form>
<script language="JavaScript" type="text/JavaScript"> function selectb()
{
alert(document.myform.myselect.value);
}
</script>
<select name="myselect" onchange="javascript:selectb()>
<option value='myparam1'>param1</option>
<option value='myparam2'>param2</option>
</select>
</form>
<script language="JavaScript" type="text/JavaScript"> function selectb()
{
if(document.myform.myselect.value == "myparam1")
alert(document.myform.myselect.value);
elseif(document.myform.myselect.value == "myparam2")
alert(document.myform.myselect.value);
else
document.write("null");
}
</script>
<?echo "<script language='javascript'>";
echo "alert('".$param."');";
echo "</script>";
?>