function clearDropDown(dropdown)
{
 var i;
    for(i=document.getElementById(dropdown).length-1;i>=0;i--)
    {
    document.getElementById(dropdown).remove(i);
    }
}


function addDropDownItem(dropdown, text, value)
{
     var y=document.createElement('option');
     y.text=text;
     y.value=value;
  try
    {
    document.getElementById(dropdown).add(y,null); // standards compliant
    }
  catch(ex)
    {
    document.getElementById(dropdown).add(y); // IE only
    }

}

function fillDropDown(result,dropdown)
{

var apts = result.split("!");


    clearDropDown(dropdown + "_apt");
 addDropDownItem(dropdown  + "_apt","Select Airport","x");
  for (var i=0; i<apts.length-1; i++) {

       var apt = apts[i].split("?");

 addDropDownItem(dropdown  + "_apt",apt[0],apt[1]);


     }


 document.getElementById(dropdown).disabled = false;
 document.getElementById(dropdown + "_apt").disabled = false;
 //document.getElementById(dropdown).onchange = "";
}



function getAirportsForContinent(deparr,postback)
{
var selIndex = document.getElementById(deparr).selectedIndex;
var selContID = document.getElementById(deparr)[selIndex].value;


clearDropDown(deparr + "_apt");

addDropDownItem(deparr + "_apt","Loading...","x");

 document.getElementById(deparr + "_apt").disabled = true;


var XHR = createXHR();
var SPostBody = encodeNameAndValue("contid",selContID);


XHR.open("post","includes/deparr_dropdown.php",true)
    XHR.setRequestHeader("Content-Type", "application/x-www-form-urlencoded");

       XHR.onreadystatechange = function () {
            if (XHR.readyState == 4) {

                if (XHR.status == 200 || XHR.status == 304) {
//alert(XHR.responseText);
             fillDropDown(XHR.responseText, deparr);

              if(postback.length==3){

            for(var i = 0; i < document.getElementById(deparr + "_apt").length; i++) {

		if(document.getElementById(deparr + "_apt")[i].value == postback) {
		  document.getElementById(deparr + "_apt").selectedIndex = i;
          }
		}
    }
               } else {
                alert("An error occurred: " + XHR.statusText);
                 }
             }
         };
    XHR.send(SPostBody);



}

function setDropdowns(depcont,dep,arrcont,arr)
{
   for(var i = 0; i < document.getElementById("depart_sel").length; i++) {
		if(document.getElementById("depart_sel")[i].value == depcont) {
		  document.getElementById("depart_sel").selectedIndex = i;
          getAirportsForContinent("depart_sel",dep);}
		}
     for(var i = 0; i < document.getElementById("arrive_sel").length; i++) {
		if(document.getElementById("arrive_sel")[i].value == arrcont) {
		  document.getElementById("arrive_sel").selectedIndex = i;
          getAirportsForContinent("arrive_sel",arr);}
		}


}