Execute multiple jQuery AJAX call one after the end of other in ASP.Net using C# and VB.Net

when i added multiple ajax function is not working.

what is the reason? how to solve this? .

here i want to load function1() data first, followed by function2() data in the webpage..reply plzz.

 $(document).ready(function () {
    function1(),
    function2()
 });
        function function1() {
            $.ajax({
                type: "POST",
                contentType: "application/json; charset=utf-8",
                url: "WebService.asmx/f1",
                data: {},
                dataType: "json",
                success: function (data) {
                    
                },
                error: function () {
                    alert("Error while Showing update data");
                }
            });
        }
function function2() {
    $.ajax({
        type: "POST",
        url: "WebService.asmx/f2",
        data: '{}',
        contentType: "application/json; charset=utf-8",
        dataType: "json",
        //success: OnSuccess,
        success: function (data) {
            
        },
        
        error: function (response) {
            alert("Error");
        }
    });
 }