function urlencode(s) {
  s = encodeURIComponent(s);
  return s.replace(/~/g,'%7E').replace(/%20/g,'+');
 }

function get_request_element() { 
	var xmlHttp;
	try {
		xmlHttp=new XMLHttpRequest();
	} // Firefox, Opera 8.0+, Safari
	catch (e) {
  		try {
    		xmlHttp=new ActiveXObject("Msxml2.XMLHTTP");
    	} // Internet Explorer
  		catch (e){
    		try {
      		xmlHttp=new ActiveXObject("Microsoft.XMLHTTP");
      	}
    		catch (e){
      		alert("Your browser does not support AJAX!");
      		return false;
      	}
    	}
  	}
  	xmlHttp.set_request_function = function(func) {
  		this.onreadystatechange = func;
  	}
  	xmlHttp.parameters = "";
  	xmlHttp.set_parameter = function(name,value) {
  		this.parameters+=name+'='+urlencode(value)+'&';
  	}
  	xmlHttp.clear_parameters = function() {
  		this.parameters = "";
  	}
  	
  	xmlHttp.url="";
  	xmlHttp.set_url = function(url) {
  		this.url=url;
  	}
 
  	xmlHttp.go = function() {
  		//var parameters="name="+urlencode(document.myForm.text.value);	
  		xmlHttp.open("GET",this.url+'?'+xmlHttp.parameters,true);
  		xmlHttp.send(null);
  	}
  	return xmlHttp;
}  
var ajax;