script fungerer ikke i netscape + firefox

Jeg har et script som kun virker i IE, men ikke i netscape, og ville gerne have det til at virke begge steder:

Jeg har 3 dropdown boxe på min side. Den første er fyldt når siden loades, når 2 fyldes med værdier afhængig af valg i nummer 1 etc.

Den første box bliver fyldt ok, men når man har valgt en værdi i box no. 1 kommer der ingen værdier i box no. 2... Kan nogen løse dette???

koden er her:

//put items into the arrays...
var arrItems1 = new Array();
var arrItemsGrp1 = new Array();
var arrItemsLocID1 = new Array();


        arrItemsLocID1[0] = "1";
        arrItems1[0] = "36";
        arrItemsGrp1[0] = "2";
     
        arrItemsLocID1[1] = "15";
        arrItems1[1] = "225";
        arrItemsGrp1[1] = "16";
     
        arrItemsLocID1[2] = "15";
        arrItems1[2] = "325";
        arrItemsGrp1[2] = "24";
     
        arrItemsLocID1[3] = "15";
        arrItems1[3] = "318";
        arrItemsGrp1[3] = "22";
     
        arrItemsLocID1[4] = "15";
        arrItems1[4] = "41";
        arrItemsGrp1[4] = "27";
     
        arrItemsLocID1[5] = "15";
        arrItems1[5] = "118";
        arrItemsGrp1[5] = "29";
     

var arrItems2 = new Array();
var arrItemsGrp2 = new Array();
var arrItemsLocID2 = new Array();


        arrItemsLocID2[0] = "2";
        arrItems2[0] = "1";
        arrItemsGrp2[0] = "3";
     
        arrItemsLocID2[1] = "2";
        arrItems2[1] = "2";
        arrItemsGrp2[1] = "4";
     
        arrItemsLocID2[2] = "2";
        arrItems2[2] = "3";
        arrItemsGrp2[2] = "5";
     
        arrItemsLocID2[3] = "2";
        arrItems2[3] = "4";
        arrItemsGrp2[3] = "6";
     
        arrItemsLocID2[4] = "2";
        arrItems2[4] = "5";
        arrItemsGrp2[4] = "7";
     
        arrItemsLocID2[5] = "2";
        arrItems2[5] = "6";
        arrItemsGrp2[5] = "8";
     
        arrItemsLocID2[6] = "2";
        arrItems2[6] = "7";
        arrItemsGrp2[6] = "9";
     
        arrItemsLocID2[7] = "2";
        arrItems2[7] = "8";
        arrItemsGrp2[7] = "10";
     
        arrItemsLocID2[8] = "2";
        arrItems2[8] = "12";
        arrItemsGrp2[8] = "11";
     
        arrItemsLocID2[9] = "2";
        arrItems2[9] = "13";
        arrItemsGrp2[9] = "12";
     
        arrItemsLocID2[10] = "2";
        arrItems2[10] = "K";
        arrItemsGrp2[10] = "13";
     
        arrItemsLocID2[11] = "2";
        arrItems2[11] = "9";
        arrItemsGrp2[11] = "14";
     
        arrItemsLocID2[12] = "16";
        arrItems2[12] = "1 syre";
        arrItemsGrp2[12] = "17";
     
        arrItemsLocID2[13] = "16";
        arrItems2[13] = "1";
        arrItemsGrp2[13] = "18";
     
        arrItemsLocID2[14] = "16";
        arrItems2[14] = "2";
        arrItemsGrp2[14] = "19";
     
        arrItemsLocID2[15] = "16";
        arrItems2[15] = "K";
        arrItemsGrp2[15] = "20";
     
        arrItemsLocID2[16] = "22";
        arrItems2[16] = "Dummy";
        arrItemsGrp2[16] = "23";
     
        arrItemsLocID2[17] = "24";
        arrItems2[17] = "k";
        arrItemsGrp2[17] = "25";
     
        arrItemsLocID2[18] = "22";
        arrItems2[18] = "k";
        arrItemsGrp2[18] = "26";
     
        arrItemsLocID2[19] = "27";
        arrItems2[19] = "dummy";
        arrItemsGrp2[19] = "28";
     
        arrItemsLocID2[20] = "29";
        arrItems2[20] = "dummy";
        arrItemsGrp2[20] = "30";
     

function selectChange(control, controlToPopulate, ItemArray, GroupArray)
{
  var myEle ;
  var x ;
  // Empty the second drop down box of any choices
  for (var q=controlToPopulate.options.length;q>=0;q--) controlToPopulate.options[q]=null;
  if (control.name == "firstChoice") {
    // Empty the third drop down box of any choices
    for (var q=locationChoices.thirdChoice.options.length;q>=0;q--) locationChoices.thirdChoice.options[q] = null;
}
  // ADD Default Choice - in case there are no values
  myEle = document.createElement("option") ;
  myEle.value = 0 ;
  myEle.text = "[SELECT]" ;
  controlToPopulate.add(myEle);
  // Now loop through the array of individual items
  // Any containing the same child id are added to
  // the second dropdown box
  for ( x = 0 ; x < ItemArray.length  ; x++ )
    {
      if(control.name == "firstChoice")
      {
        if ( arrItemsLocID1[x] == control.value )
          {
            myEle = document.createElement("option") ;
            myEle.value = GroupArray[x];
            myEle.text = ItemArray[x] ;
            controlToPopulate.add(myEle) ;
          }
      }

      if(control.name == "secondChoice")
      {
        if ( arrItemsLocID2[x] == control.value )
          {
            myEle = document.createElement("option") ;
            myEle.value = GroupArray[x];
            myEle.text = ItemArray[x] ;
            controlToPopulate.add(myEle) ;
          }
      }
     
    }
}


------------------------------------------------------------

her er de 3 select boxe som er på html siden...

<select id="firstChoice" name="firstChoice" tabindex="2" onchange="selectChange(this, locationChoices.secondChoice, arrItems1, arrItemsGrp1);">
                <option value="X" selected>[SELECT]</option>
               
                        <option value="1">11</option>
                     
                        <option value="15">30</option>
                     
                </select>
                <select id="secondChoice" name="secondChoice" tabindex="3" onchange="selectChange(this, locationChoices.thirdChoice, arrItems2, arrItemsGrp2);">
                <option>[SELECT]</option>
                </select>
                <select id="thirdChoice" name="thirdChoice" tabindex="4" ></select>