function serverCall_get(url, functionToCallBack) {
		
			var http_request = false;
		
			if (window.XMLHttpRequest) { // Mozilla, Safari,...
				http_request = new XMLHttpRequest();
				if (http_request.overrideMimeType) 
					http_request.overrideMimeType('text/html');
			} else if (window.ActiveXObject) { // IE
				try {
					http_request = new ActiveXObject("Msxml2.XMLHTTP");
				} catch (e) {
					try {
						http_request = new ActiveXObject("Microsoft.XMLHTTP");
					} catch (e) {}
				}
			}
			if (!http_request) {
				alert('Cannot create XMLHTTP instance');
				return false;
			}
			
			http_request.onreadystatechange = function()
			{
				if (http_request.readyState == 4)
					if (http_request.status == 200){
						functionToCallBack(http_request.responseText); 
				        delete http_request;
				        http_request = null;
					}
			}
			http_request.open('GET', url, true);
			http_request.send(null);
		}
		
		function serverCall_post(url, parameters, functionToCallBack) {

			http_request = false;
			
			if (window.XMLHttpRequest) { // Mozilla, Safari,...
				http_request = new XMLHttpRequest();
				if (http_request.overrideMimeType) 
					http_request.overrideMimeType('text/html');
			} else if (window.ActiveXObject) { // IE
				try {
					http_request = new ActiveXObject("Msxml2.XMLHTTP");
				} catch (e) {
					try {
						http_request = new ActiveXObject("Microsoft.XMLHTTP");
					} catch (e) {}
				}
			}
			if (!http_request) {
				alert('Cannot create XMLHTTP instance');
				return false;
			}
			
			http_request.onreadystatechange = function()
			{
				if (http_request.readyState == 4)
					if (http_request.status == 200){
						functionToCallBack(http_request.responseText); 
				        delete http_request;
				        http_request = null;
					}
			}
			http_request.open('POST', url, true);
			http_request.setRequestHeader("Content-type", "application/x-www-form-urlencoded");
			http_request.setRequestHeader("Content-length", parameters.length);
			http_request.setRequestHeader("Connection", "close");
			http_request.send(parameters);
		}