function ajaxComboBoxCidades(param_formObj,param_phpUrl,param_phpQuery) {

	var ajax;  // The variable that makes Ajax possible!
	
	try{
		// Opera 8.0+, Firefox, Safari
		ajax = new XMLHttpRequest();
	} catch (e){
		// Internet Explorer Browsers
		try{
			ajax = new ActiveXObject("Msxml2.XMLHTTP");
		} catch (e) {
			try{
				ajax = new ActiveXObject("Microsoft.XMLHTTP");
			} catch (e){
				// Something went wrong
				alert("Seu browser não suporta Ajax!");
				return false;
			}
		}
	}
	
	document.getElementById(param_formObj).disabled = "disabled";
	
	// Create a function that will receive data sent from the server
	ajax.onreadystatechange = function(){
		
		if(ajax.readyState == 1){
			setAjaxLoader(true);
		}
		
		if(ajax.readyState == 4){
			if(ajax.responseXML){
				processXML(ajax.responseXML,param_formObj);
			}else{
				alert('Não foi possível ler o Xml de resultados!');
				//alert(param_formObj+'\n'+param_phpUrl+'\n'+param_phpQuery);
			}
		}
		//alert('ajax.readyState: '+ajax.readyState);
	}
	ajaxQueryUrl	= param_phpUrl+'?cod_estado='+param_phpQuery;
	//alert(ajaxQueryUrl);
	ajax.open("GET", ajaxQueryUrl, true);
	ajax.send(null); 

}

function processXML(responseXML,param_formObj){
	
  	var dataArray = responseXML.getElementsByTagName("option");

	if(dataArray.length > 0){
		
		document.getElementById(param_formObj).length = 0;
		
		///////////////////////////////////////////////////////////
		// Adiciona opções vazias /////////////////////////////////
		///////////////////////////////////////////////////////////
		var newOpt = document.createElement("option");
		newOpt.value 		= "";
		newOpt.text 		= "Selecione uma cidade";
		document.getElementById(param_formObj).options.add(newOpt);
		
		var newOpt = document.createElement("option");
		newOpt.value 		= "";
		newOpt.text 		= "";
		newOpt.className	= "emptyOption"
		document.getElementById(param_formObj).options.add(newOpt);
		
		var newOpt = document.createElement("option");
		newOpt.value 		= "";
		newOpt.text 		= "";
		document.getElementById(param_formObj).options.add(newOpt);
		///////////////////////////////////////////////////////////
		
		for(var i = 0; i < dataArray.length; i++){
			var item = dataArray[i];
			var cod_cidade 	= item.getElementsByTagName("cod_cidade")[0].firstChild.nodeValue;
			var dsc_nome 	= item.getElementsByTagName("dsc_nome")[0].firstChild.nodeValue;
			var newOpt = document.createElement("option");
			newOpt.value 	= cod_cidade;
			newOpt.text 	= dsc_nome;
			document.getElementById(param_formObj).options.add(newOpt);
		}
		document.getElementById(param_formObj).disabled = "";
		setAjaxLoader(false);
  	}else{
    	setAjaxLoader(false);
  	}
}

function setAjaxLoader(status){
	if(status){
		document.getElementById("ajaxStatusBox").style.height	= document.body.offsetHeight+"px";
		document.getElementById("ajaxStatusBox").style.display 	= "block";
	}else{
		//caso o XML volte vazio, printa a mensagem abaixo
		document.getElementById("ajaxStatusBox").style.display 	= "none";
	}
}