Can I wait for $.get() call before submitting the form?

I have a sign-up form which prompts for the first name, last name, username, password and e-mail address. I'm using two separate $.get() methods to check if the username and e-mail address are not existing.

This is my function:

 function validateSignUp() {
        var firstName = $("#first-name").val();
        var lastName = $("#last-name").val();
        var username = $("#username").val();
        var password = $("#pass").val();
        var email = $("#email").val();
        var passwordVerifier = $("#retype-pass").val();
        var emailVerifier = $("#retype-email").val();

        errorMessage = "";
        var isUsernameValid = validateUsername(username);

        var isError = false;

        // validate first name field
        if (firstName == "" || lastName == "") {
            isError = true;
            $("#error-message").html("All fields are required");
        }

        // validate password
        if (validatePassword(password) == false) {
            isError = true;
            $("#check-password").html("Password is invalid");
        }
        else {
            $("#check-password").html("");
        }

        // validate password verifier
        if (passwordVerifier == password) {
            if (validatePassword(passwordVerifier) == false) {
                isError = true;
                $("#recheck-password").html("Minimum of 6 characters and maximum of 30 characters");
            }
            else {
                if (password != passwordVerifier) {
                    isError = true;
                    $("#recheck-password").html("Minimum of 6 characters and maximum of 30 characters ");
                }
                else {
                    $("#recheck-password").html("");
                }
            }
        }
        else {
            isError = true;
            $("#recheck-password").html("Passwords didn't match");
        }

        // validate username field
        if (isUsernameValid == false) {
            isError = true;
            $("#check-username").html("Alphanumeric characters only");
        } // if
        else if (isUsernameValid == true) {
            $.get("/account/checkavailabilitybyusername", { username: username },
                    function(data) {
                        if (data == "Not Existing") {
                            $("#check-username").html("");
                        }
                        else if (data == username) {
                            isError = true;
                            $("#check-username").html("Sorry, this username is already registered");
                        }
                    }
                    );
        } // else
        // validate e-mail address field

        if (validateEmail(email) == false) {
            isError = true;
            $("#check-email").html("Sorry, the e-mail you typed is invalid");
        } // if
        else if (validateEmail(email) == true) {
        $.get("/account/checkavailabilitybyemail", { email: email },
                    function(data) {
        if (data == "Not Existing") {
                            $("#check-email").html("");
                        }
                        else if (data == email) {
                        isError = true;
                            $("#check-email").html("Sorry, this e-mail is already registered");
                        }
                    });
                }
                if (isError == true) {
                    return false;
              开发者_运维技巧  }
        return true;
   }

When other fields are blank and the username and/or e-mail address is existing, the form is not submitted. And the callback functions of the get methods are called as well. But when I'm going to submit my form with no empty fields, it is automatically submitted without checking the username and/or e-mail by $.get(). Is there anything wrong with my function or I'm not yet discovering something. Thanks.

You need to use a full ajax() call and set the async property to false. This makes your request synchronous, i.e. it forces the browser to wait until doing anything else. Try this:

 $.ajax({
     url: "/account/checkavailabilitybyemail",
     data: { email: email },
     async: false,
     success: function(data) {
         if (data == "Not Existing") {
             $("#check-email").html("");
         } else if (data == email) {
             isError = true;
             $("#check-email").html("Sorry, this e-mail is already registered");
         }
     })
 });

 if (isError == true) {
      return false;
 }

I suggest you leverage Jquery validate with two remote rules. It's quite easy to implement and a very mature plugin. This way you can focus on other aspects of your UX and not have to re implement this validation logic should you need to validate another form in your project.

Inside your main function, you cannot directly wait for the $.get() to return. But you can move the form submission to the success callback of the AJAX call (assuming form to contain a reference to the actual form element):

$.get("/account/checkavailabilitybyusername", { username: username },
                    function(data) {
                        if (data == "Not Existing") {
                            $("#check-username").html("");
                            form.submit();
//--------------------------^
                        }
                        else if (data == username) {
                            isError = true;
                            $("#check-username").html("Sorry, this username is already registered");
                        }
                    }
                    );

Note however, that then the form submission depends on the AJAX to return. Most useful would be a timeout (with window.setTimeout()) and a server-side validation, if the JS doesn't respond or the user has JS disabled.