function createCORSRequest(method, url){
    var xhr = new XMLHttpRequest();

    if ("withCredentials" in xhr){
        xhr.open(method, url, true);
    } else if (typeof XDomainRequest != "undefined"){
        xhr = new XDomainRequest();
        xhr.open(method, url);
    } else {
        xhr = null;
    }

    return xhr;
}

function CallWS(){

    var request = createCORSRequest("POST","https://**************/gateway.com");
    if (request){
        request.onload = function(){
            var res = request.responseText;
            alert(res);
        };
        request.send();
    }