AJAX成功响应文本

Question

Right now I'm modifying my AJAX request to be asynchronous but I wanted to know if there was something similar to var reponse = $.ajax({ in success. Before I had my code as:

     var response = $.ajax({
           type : "GET",
           url : url,
           data : parameters,
           cache : false,
           async : false
    }).responseText;

return response;

I tried doing using the first data argument but that just returns the parameters. Is there something similar I can use in success?

success : function(response) {
     callBack(response); 
}

Answer 1

Because the request is asynchronous you cannot just return the response.

jQuery uses something called "promises", which you can return instead:

function getUser(id) {
    return $.ajax({
        url: "/user",
        data: { id:id },
    });
}

So, whenever you want to get a user you just call the function:

var userRequest = getUser(123);

The userRequest variable now contains a "future promise". In other words, sometime in the future it will be ready for you to use it.

You cannot use it straight away but you can create a function that will run when it finally is ready. That is done using the .done() method:

userRequest.done(function (user) {
    console.log("The user " + user.name + " has been loaded!");
});

If you, for example, also want to load the user's profile alongside the user then you can create two requests and then use the $.when() method:

var userRequest    = getUser(123).
    profileRequest = getProfileForUser(123);

$.when(userRequest, profileRequest).done(function (user, profile) {
    console.log(user.name + " is " + profile.age + " years old");
});

Read more about promises over at jQuery .