How can i call multiple code behind method from javascript

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C#

ASP.NET

Javascript

How can I call multiple code behind method from JavaScript?

Currently I am using
But I think first second method is call simultaneously,
what I want, if first method is called successfully then
only second method should be called.

So how can I make this possible?

Code below:

function OnResetDataClick() {
      var UserEmail = document.getElementById("ContentPlaceHolder1_UserName1");
      var val = UserEmail.value;
      var usedata= "";

      var reg = /^([A-Za-z0-9_\-\.])+\@([A-Za-z0-9_\-\.])+\.([A-Za-z]{2,4})$/;
      if (reg.test(val) == false) {
      }
      else {
        
        var getPassword = {
          type: "POST",
          url: "GetData.aspx/GetDataMethod",
          data: "",
          contentType: "application/json; charset=utf-8",
          dataType: "json",
          success: function (response) {
            usedata= response.d;

          },
          error: function (result) {
            alert("Error");
          }
        };

        //Call the PageMethods
        $.ajax(getPassword);
       
      // Calling second Page Method
      if (usedata!= "") {
        var options = {
          type: "POST",
          url: "GetData.aspx/SendData",
          data: "{'toMailAddress':'" + val + "','usefulldata':'" + usedata+ "'}",
          contentType: "application/json; charset=utf-8",
          dataType: "json",
          success: function (response) {
            var val1 = response.d;
            alert(val1);
          },
          error: function (result) {
            alert("Error in " + result);
          }
        };

        //Call the PageMethods
        $.ajax(options);
        // }
      }

    }