jQuery.support.cors = true;
    var pageUrl = 'http://webservice.svn/WebService1.asmx';

    $.ajax({
        type: "POST",
        url: pageUrl + "/Helloworld",
        data: '{}',
        contentType: "application/json; charset=utf-8",
        dataType: "json",
        success: function (response) {
            alert(response.d);
        },
        error: function (response) {
            alert(response.status + " " + response.statusText);
        }
    });