สอบถามการ ใช้ onchange โดยใช้ listmenu แล้วแสดงค่าใน textbox

        <script type="text/javascript">
///เรียกใช้  Texbox ถ้าไม่ต้องการก็ไม่ต้องเลือก Radio 
	function ck_frm(){
		var ck = document.getElementById('Other');
		if(ck.checked == true){
		document.getElementById('frm_txt').style.display = "";
		}else{
		document.getElementById('frm_txt').style.display = "none";
		}

	}
</script>

	<select id="Plants" name="Plants" onChange = "ListProvince(this.value)">
	<option onclick="document.getElementById('Other').style.display='none'" selected value="">-->select Plants<--</option>
	<?
	$strSQLk = "SELECT * FROM Tb_plants ORDER BY Id_munber ASC ";
	$objQueryk = mysql_query($strSQLk) or die ("Error Query [".$strSQLk."]");
	while($objResultk = mysql_fetch_array($objQueryk))
	{
	?>
	<option onclick="document.getElementById('Other').style.display='none'" value="<?=$objResultk["Id_type_valu"];?>"><?=$objResultk["Name_label"];?></option>
	<?
	}
	?>
    <option value="" onclick="document.getElementById('Other').style.display=''">-->Other</option>
	</select>

             <select name="fname" id="fname" onChange="bind(this)" >  
					 <option  value="" id="s0<?= $fname ?>" >-- Select --</option> 
						<?php  
                            $q="select fname from tb_customer ";  
                            $qr=mysql_query($q);  
                            while($rs=mysql_fetch_array($qr)){  
                        ?>
                          <option value="<?=$rs['fname']?>"><?=$rs['fname']?></option> 
                        <?php } ?>      
              </select>

<input name="cus" type="text" id="cus" size="20" readonly/>

<script language="javascript">
function bind(objSelect){
	  document.getElementById("cus").value = objSelect.options[objSelect.selectedIndex].value;
}
</script>