jQuery: Performing synchronous AJAX requests

问题

I\'ve done some jQuery in the past, but I am completely stuck on this. I know about the pros and cons of using synchronous ajax calls, but here it will be required.

The remote page is loaded (controlled with firebug), but no return is shown.

What should I do different to make my function to return properly?

function getRemote() {

    var remote;

    $.ajax({
        type: \"GET\",
        url: remote_url,
        async: false,
        success : function(data) {
            remote = data;
        }
    });

    return remote;

}

回答1:

As you're making a synchronous request, that should be

function getRemote() {
    return $.ajax({
        type: "GET",
        url: remote_url,
        async: false
    }).responseText;
}

Example - http://api.jquery.com/jQuery.ajax/#example-3

PLEASE NOTE: Setting async property to false is deprecated and in the process of being removed (link). Many browsers including Firefox and Chrome have already started to print a warning in the console if you use this:

Chrome:

Synchronous XMLHttpRequest on the main thread is deprecated because of its detrimental effects to the end user's experience. For more help, check https://xhr.spec.whatwg.org/.

Firefox:

Synchronous XMLHttpRequest on the main thread is deprecated because of its detrimental effects to the end user’s experience. For more help http://xhr.spec.whatwg.org/

回答2:

You're using the ajax function incorrectly. Since it's synchronous it'll return the data inline like so:

var remote = $.ajax({
    type: "GET",
    url: remote_url,
    async: false
}).responseText;

回答3:

how remote is that url ? is it from the same domain ? the code looks okay

try this

$.ajaxSetup({async:false});
$.get(remote_url, function(data) { remote = data; });
// or
remote = $.get(remote_url).responseText;

回答4:

function getRemote() {
    return $.ajax({
        type: "GET",
        url: remote_url,
        async: false,
        success: function (result) {
            /* if result is a JSon object */
            if (result.valid)
                return true;
            else
                return false;
        }
    });
}

来源：https://stackoverflow.com/questions/6685249/jquery-performing-synchronous-ajax-requests

标签

ajax

jquery

synchronous