var xmlhttp = Array();
var target = Array();

function ajaxAction(url, params, displayTarget, indexToUse)
{
	//setting the target element
	if(indexToUse == '' || indexToUse == undefined)
	{
		var index = target.length; //count will always be equal to the next available index as the index starts from 0
	}
	else
	{
		var index = indexToUse;
	}
	
	//Creating the target with the next available index.
	target[index] = displayTarget;
	
	//creating the xmlHttp request for the current index. Remember, a new request should not overwrite the old one when there are more than one requests at the same time.
	xmlhttp[index]=GetXmlHttpObject();
	
	if (xmlhttp[index]==null)
	{
		alert ("Browser does not support HTTP Request");
		return;
	}
	
	params=params+"&sid="+Math.random();

	xmlhttp[index].open("GET",url+'?'+params,false);
	xmlhttp[index].send(null);
	return xmlhttp[index].responseText;
}

function GetXmlHttpObject()
{
	if (window.XMLHttpRequest)
	{
		// code for IE7+, Firefox, Chrome, Opera, Safari
		return new XMLHttpRequest();
		}
	if(window.ActiveXObject)
	{
		// code for IE6, IE5
		return new ActiveXObject("Microsoft.XMLHTTP");
	}
	
	return null;
}

function callAjax(id_cliente, id_ruta, id_servicio, peso, volumen, fob)
{
	var url = 'js/getTarifaValue.php';
	var params = 'id_cliente='+id_cliente+'&id_ruta='+id_ruta+'&id_servicio='+id_servicio+'&peso='+peso+'&volumen='+volumen+'&fob='+fob;
	var displayTarget = 'test';
	
	return ajaxAction(url, params, displayTarget, 'test');
	
}

function checkUser(id_cliente, contrasena)
{
	var url = 'js/authUser.php';
	var params = 'id_cliente='+id_cliente+'&contrasena='+contrasena+'&user_type='+user_type;
	var displayTarget = '';
	var result;
	
	result = ajaxAction(url, params, displayTarget, 'test');
	
	//sending output to the browser 
	document.getElementById('test').innerHTML = result;
}