//globals

//
function sendRequest(url,params,HttpMethod) {
	if(!HttpMethod) { //check if http method is defined, if not, set it to GET
	   HttpMethod="GET";
	}
	//
	// initialize request object
	req=null;
	// code for IE7+, Firefox, Chrome, Opera, Safari
	if(window.XMLHttpRequest){
	   req=new XMLHttpRequest(); //mozilla/safari
	} 
	
	// code for IE6, IE5
	if(window.ActiveXObject){
	   req=new ActiveXObject("Microsoft.XMLHTTP"); //internet explorer
	}

	//
	//define callback handler
	if(req) {
	//
	   req.onreadystatechange=onReadystate;
	   req.open(HttpMethod,url,true);
	   req.setRequestHeader("Content-Type","application/x-www-form-urlencoded");
	   req.send(params);
	} 
}

//
function onReadystate() {
//
var ready=req.readyState;
var data=null;
	if(ready==4){ //check ready state
		data=req.responseText; //read response data
		var items = data.split(',');

		var select = document.getElementById(items[0]);
		// Set Default item for target Combo
		select.options[select.options.length] = new Option('Choose '+items[0],'*');

		var length = items.length;
		for(var i = 1; i < length; i++) {
			// Add each array Item to end of Combobox
			select.options[select.options.length] = new Option(items[i], items[i]);
	   }
	}
}

function initCombo(oCombo,oName){
	
	while(oCombo.hasChildNodes()) { //removes items from dropdown if some already exist
	   oCombo.removeChild(oCombo.firstChild);
	}

	var select = document.FrmSearch.oName;
	select.options[select.options.length] = new Option(oName +' First','*');

//   oCombo.disabled=1;
}


// ######  Check if a Combo has been selected  ######
function comboData(oSrc,oDest) {
//
var combSrc = document.getElementById(oSrc);
var combDest = document.getElementById(oDest);
var selected = combSrc.selectedIndex;
//
//
	while(combDest.hasChildNodes()) { //removes items from dropdown if some already exist
	   combDest.removeChild(combDest.firstChild);
	}
	if(selected!= 0) { //if they choose something other than the first select-->"Select topic first"
	   
	   sendRequest('ajsrchdata.php?srcfld='+oSrc+'&dstfld='+oDest+'&data='+combSrc.options[selected].value);
//	   combDest.disabled=0;
	} else { //otherwise add the Select Topic First option and disable it
		var childEl = document.createElement('option');
		combDest.appendChild(childEl);
		childEl.value = '*';
		childEl.innerHTML = 'Select '+oSrc+' First';
//		combDest.disabled=1;
		var select = document.FrmSearch.oDest;
		select.options[select.options.length] = new Option('Select '+oSrc+' First','*');
	}
	
}