I am struggling a little with a form with drop down menus for billing and shipping states. I have a Same as Shipping Address button. All fields expect the billing state drop down auto fill when clicked in IE. It works as planned in Firefox and Chrome, but does not work in any version of IE. It simply changes the value to blank. Any help is greatly appreciated.

The Javascript:
<script type="text/javascript">
// <!--
function billsame(form){

     form.name.value = form.nametoship.value;
     form.address.value = form.addresstoship.value;
     form.city.value = form.citytoship.value;  
     form.zip.value = form.ziptoship.value;
    document.getElementById('state').value = document.getElementById('statetoship').value; 

     form.name.value = "";
     form.address.value = "";
     form.city.value = "";  
     form.zip.value = "";
     form.state.value = "";
The Same As Button:
<input type="checkbox" name="sameasshipping" value="checkbox" onClick="billsame(this.form);">Same as Shipping Address
The Drop Down Menus:
 	 	echo "State&nbsp;&nbsp;&nbsp;&nbsp;\n";
    echo "<select name=\"statetoshipdrop\" id=\"statetoship\" disabled>";  
       echo '<option selected="">Select Your State</option>';  
       $statesa = statesList();  
        foreach($statesa as $keya=>$valuea) {  
        	if ($keya==$statetoship) {
        		$selecteda=" selected=\"selected\" ";
				} else {
	echo "<option $selecteda>$keya</option>";
   echo '</select>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<br><br>';  


 	echo "State&nbsp;&nbsp;&nbsp;&nbsp;\n";
    echo '<select name="state" id="state">';  
        echo '<option value="">Select Your State</option>';  
        $statesb = statesList();  
        foreach($statesb as $keyb=>$valueb) {  
        	if ($keyb==$state) {
        		echo "<option selected=\"selected\" value=\"$keyb\">$keyb</option>";
				} else {
				echo "<option value=\"$keyb\">$keyb</option>";
    echo "</select>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<br><br>";  

Thank You