JS手寫AJAX代碼

        function a() {
            var c = new XMLHttpRequest()
            c.open("get", "Default.aspx?id=2", true);
            c.setRequestHeader("If-Modified-Since", 0);
            c.onreadystatechange = function () {
                if (c.readyState == 4 && c.status == 200) {
                    var s = c.responseText;
                }
            }
        }
 
        function b()
        {
            var b = new XMLHttpRequest();
            b.open("post", "1.aspx", true);
            b.setRequestHeader("Content-Type", "application/x-www-Form-urlencoded");
            b.onreadystatechange = function ()
            {
                if(b.readyState==4&&b.status==200)
                var x = b.responseText;
 
            }
 
        }