Ajax non funziona sui smartphone

var XMLHttp=AJAXCreateReqObject();
function AJAXCreateReqObject(){
	var b=null;
	var a=navigator.userAgent.toUpperCase();
	if(window.XMLHttpRequest){
		b=new XMLHttpRequest()
	}else{
		if(window.ActiveXObject&&(a.indexOf("MSIE 4")<0)){
			if(a.indexOf("MSIE 5")<0){
				b=new ActiveXObject("Msxml2.XMLHTTP")
				}else{b=new ActiveXObject("Microsoft.XMLHTTP")
				}
			}
		}
	return(b)
};
function AJAXHandleRsp(){
			switch(XMLHttp.readyState){
				case 0:
					console.log(0);//alert("0");
					break;
				case 1:
					console.log(1);//alert("1");
					break;
				case 2:
					console.log(2); //alert("2");
					break;
				case 3:
					console.log(3); //alert("3");
					break; 
				case 4:						
					console.log(4);
					if(XMLHttp.status==200){
						SetupValues(XMLHttp.responseText)
					}	console.log("ok"); 
				break
					}
			};
function AJAXSendRequestpost(b){		
	var a=Math.random();
	var parametri  = "?Rnd="+escape(a)+"&UINT 60=" +document.getElementById("newvalore").value;
	//var parametri  = "&UINT 60=" +document.getElementById("newvalore").value;
	if(XMLHttp!=null){
		
		XMLHttp.open("POST",b,true);
		
		
		XMLHttp.setRequestHeader("Content-Type","application/x-www-form-urlencoded; charset=UTF-8");
		//XMLHttp.setRequestHeader('Content-Type', 'multipart/form-data');
		XMLHttp.onreadystatechange=AJAXHandleRsp;
		//XMLHttp.timeout = 4000;
		//XMLHttp.ontimeout = function () { alert("Timed out!!!"); }				
		XMLHttp.send(parametri);	
	
	
	}
};