javascript - setting a jquery ajax request to async = false doesn't work - Stack Overflow

admin管理员组

文章数量:1021218

I'm attempting to get started with google wallet and am generating a jwt token via an ajax request.

When a user hits the purchase button it fires the purchase() function which in turn sends off some data to get the jwt using the get_jwt_token_for_user() function. I've set the ajax request to not be asynchronous to ensure that the jwt is sent to the google payments handler.

However the purchase() function seems to continue before the jwt is returned by the get_jwt_token_for_user() function. The log output shows that the numbers 1 and 2 are printed to console before the jwt is printed to the console from the get_jwt_token_for_user() function.

function get_jwt_token_for_user(the_key)
{
    var JwtTokenURL = "/get_jwt_token";
    var the_user_name = $('#user_name').val();
    var the_user_email = $('#user_email').val();
    var the_user_number = $('#user_number').val();
    $.ajax({ 
        type: "Get",
        url: JwtTokenURL,
        data: {user_number : the_user_number, user_name : the_user_name, user_email : the_user_email, the_d_key : the_key},
        async: false,
        success: function(result) {
            var myObject = JSON.parse(result);
            console.log(myObject.jwt_token);
            return myObject.jwt_token
        },
        failure: function(fail){ alert(fail); }
     });
}

function purchase(the_key)
{
    console.log("1");
    var jwt_token = get_jwt_token_for_user(the_key);
    console.log("2");
    if (jwt_token !== "")
    {
        console.log(jwt_token);
        goog.payments.inapp.buy({
            parameters: {},
            'jwt'     : jwt_token,
            'success' : successHandler,
            'failure' : failureHandler
          });
    }
}

Any idea what I can do to ensure that the ajax request has returned the data before the purchase() function marches on without the jwt value?

I'm attempting to get started with google wallet and am generating a jwt token via an ajax request.

When a user hits the purchase button it fires the purchase() function which in turn sends off some data to get the jwt using the get_jwt_token_for_user() function. I've set the ajax request to not be asynchronous to ensure that the jwt is sent to the google payments handler.

However the purchase() function seems to continue before the jwt is returned by the get_jwt_token_for_user() function. The log output shows that the numbers 1 and 2 are printed to console before the jwt is printed to the console from the get_jwt_token_for_user() function.

function get_jwt_token_for_user(the_key)
{
    var JwtTokenURL = "/get_jwt_token";
    var the_user_name = $('#user_name').val();
    var the_user_email = $('#user_email').val();
    var the_user_number = $('#user_number').val();
    $.ajax({ 
        type: "Get",
        url: JwtTokenURL,
        data: {user_number : the_user_number, user_name : the_user_name, user_email : the_user_email, the_d_key : the_key},
        async: false,
        success: function(result) {
            var myObject = JSON.parse(result);
            console.log(myObject.jwt_token);
            return myObject.jwt_token
        },
        failure: function(fail){ alert(fail); }
     });
}

function purchase(the_key)
{
    console.log("1");
    var jwt_token = get_jwt_token_for_user(the_key);
    console.log("2");
    if (jwt_token !== "")
    {
        console.log(jwt_token);
        goog.payments.inapp.buy({
            parameters: {},
            'jwt'     : jwt_token,
            'success' : successHandler,
            'failure' : failureHandler
          });
    }
}

Any idea what I can do to ensure that the ajax request has returned the data before the purchase() function marches on without the jwt value?

• javascript
• ajax
• jquery

Share Improve this question Follow edited Jul 7, 2012 at 20:10 mu is too short 435k7171 gold badges859859 silver badges818818 bronze badges asked Jul 7, 2012 at 19:38 user714852user714852 2,15455 gold badges3131 silver badges5252 bronze badges 3

• Not sure if this will fix the async problem, but your return statement won't do any good in the success handler. I think you want it after the $.ajax() call has finished, so put it after that. Otherwise your get_jwt_token_for_user() function will always return null. – Jake Stoeffler Commented Jul 7, 2012 at 19:54
• resructure your code so the code you want to get executed go into the callback ;) – Jarry Commented Jul 7, 2012 at 19:54
• Bit confused - nothing in the code you posted actually calls the purchase function from what I can see, i.e. there are no invocations of it. – Mitya Commented Jul 7, 2012 at 19:58

Add a ment  | 

1 Answer 1

Sorted by: Reset to default 5

Your get_jwt_token_for_user function doesn't return anything, you need something more like this:

function get_jwt_token_for_user(the_key) {
    //...
    var myObject;
    $.ajax({ 
        //...
        success: function(result) {
            myObject = JSON.parse(result);
        },
        //...
     });
     return myObject ? myObject.jwt_token : '';
}

Returning something from your success callback doesn't cause that value to be returned by $.ajax and JavaScript functions do not return the value of their last expressions, you must include an explicit return if you want your function to return something.

You should also stop using async:false as soon as possible, it is rather user-hostile and it is going away. Your code should look more like this:

function get_jwt_token_for_user(the_key, callback) {
    //...
    $.ajax({ 
        type: "Get",
        url: JwtTokenURL,
        data: {user_number : the_user_number, user_name : the_user_name, user_email : the_user_email, the_d_key : the_key},
        success: function(result) {
            var myObject = JSON.parse(result);
            callback(myObject.jwt_token);
        },
        failure: function(fail){ alert(fail); }
     });
}

function purchase(the_key) {
    get_jwt_token_for_user(the_key, function(jwt_token) {
        if (jwt_token !== "") {
            //...
        }
    });
}

I'm attempting to get started with google wallet and am generating a jwt token via an ajax request.

When a user hits the purchase button it fires the purchase() function which in turn sends off some data to get the jwt using the get_jwt_token_for_user() function. I've set the ajax request to not be asynchronous to ensure that the jwt is sent to the google payments handler.

However the purchase() function seems to continue before the jwt is returned by the get_jwt_token_for_user() function. The log output shows that the numbers 1 and 2 are printed to console before the jwt is printed to the console from the get_jwt_token_for_user() function.

function get_jwt_token_for_user(the_key)
{
    var JwtTokenURL = "/get_jwt_token";
    var the_user_name = $('#user_name').val();
    var the_user_email = $('#user_email').val();
    var the_user_number = $('#user_number').val();
    $.ajax({ 
        type: "Get",
        url: JwtTokenURL,
        data: {user_number : the_user_number, user_name : the_user_name, user_email : the_user_email, the_d_key : the_key},
        async: false,
        success: function(result) {
            var myObject = JSON.parse(result);
            console.log(myObject.jwt_token);
            return myObject.jwt_token
        },
        failure: function(fail){ alert(fail); }
     });
}

function purchase(the_key)
{
    console.log("1");
    var jwt_token = get_jwt_token_for_user(the_key);
    console.log("2");
    if (jwt_token !== "")
    {
        console.log(jwt_token);
        goog.payments.inapp.buy({
            parameters: {},
            'jwt'     : jwt_token,
            'success' : successHandler,
            'failure' : failureHandler
          });
    }
}

Any idea what I can do to ensure that the ajax request has returned the data before the purchase() function marches on without the jwt value?

I'm attempting to get started with google wallet and am generating a jwt token via an ajax request.

When a user hits the purchase button it fires the purchase() function which in turn sends off some data to get the jwt using the get_jwt_token_for_user() function. I've set the ajax request to not be asynchronous to ensure that the jwt is sent to the google payments handler.

However the purchase() function seems to continue before the jwt is returned by the get_jwt_token_for_user() function. The log output shows that the numbers 1 and 2 are printed to console before the jwt is printed to the console from the get_jwt_token_for_user() function.

function get_jwt_token_for_user(the_key)
{
    var JwtTokenURL = "/get_jwt_token";
    var the_user_name = $('#user_name').val();
    var the_user_email = $('#user_email').val();
    var the_user_number = $('#user_number').val();
    $.ajax({ 
        type: "Get",
        url: JwtTokenURL,
        data: {user_number : the_user_number, user_name : the_user_name, user_email : the_user_email, the_d_key : the_key},
        async: false,
        success: function(result) {
            var myObject = JSON.parse(result);
            console.log(myObject.jwt_token);
            return myObject.jwt_token
        },
        failure: function(fail){ alert(fail); }
     });
}

function purchase(the_key)
{
    console.log("1");
    var jwt_token = get_jwt_token_for_user(the_key);
    console.log("2");
    if (jwt_token !== "")
    {
        console.log(jwt_token);
        goog.payments.inapp.buy({
            parameters: {},
            'jwt'     : jwt_token,
            'success' : successHandler,
            'failure' : failureHandler
          });
    }
}

Any idea what I can do to ensure that the ajax request has returned the data before the purchase() function marches on without the jwt value?

• javascript
• ajax
• jquery

Share Improve this question Follow edited Jul 7, 2012 at 20:10 mu is too short 435k7171 gold badges859859 silver badges818818 bronze badges asked Jul 7, 2012 at 19:38 user714852user714852 2,15455 gold badges3131 silver badges5252 bronze badges 3

• Not sure if this will fix the async problem, but your return statement won't do any good in the success handler. I think you want it after the $.ajax() call has finished, so put it after that. Otherwise your get_jwt_token_for_user() function will always return null. – Jake Stoeffler Commented Jul 7, 2012 at 19:54
• resructure your code so the code you want to get executed go into the callback ;) – Jarry Commented Jul 7, 2012 at 19:54
• Bit confused - nothing in the code you posted actually calls the purchase function from what I can see, i.e. there are no invocations of it. – Mitya Commented Jul 7, 2012 at 19:58

Add a ment  | 

1 Answer 1

Sorted by: Reset to default 5

Your get_jwt_token_for_user function doesn't return anything, you need something more like this:

function get_jwt_token_for_user(the_key) {
    //...
    var myObject;
    $.ajax({ 
        //...
        success: function(result) {
            myObject = JSON.parse(result);
        },
        //...
     });
     return myObject ? myObject.jwt_token : '';
}

Returning something from your success callback doesn't cause that value to be returned by $.ajax and JavaScript functions do not return the value of their last expressions, you must include an explicit return if you want your function to return something.

You should also stop using async:false as soon as possible, it is rather user-hostile and it is going away. Your code should look more like this:

function get_jwt_token_for_user(the_key, callback) {
    //...
    $.ajax({ 
        type: "Get",
        url: JwtTokenURL,
        data: {user_number : the_user_number, user_name : the_user_name, user_email : the_user_email, the_d_key : the_key},
        success: function(result) {
            var myObject = JSON.parse(result);
            callback(myObject.jwt_token);
        },
        failure: function(fail){ alert(fail); }
     });
}

function purchase(the_key) {
    get_jwt_token_for_user(the_key, function(jwt_token) {
        if (jwt_token !== "") {
            //...
        }
    });
}

本文标签： javascriptsetting a jquery ajax request to asyncfalse doesn39t workStack Overflow