Question

I have an if statement:

    if(authenticate_session("secret_password12345")){
        alert("You are authenticated");
    }else{
        alert("Intruder alert!");
    }

and the javascript authenticate function, which makes an jQuery POST AJAX call to the server to do the actual authentication, and returns true or false:

function authenticate_session(session_id){
 $.post("/auth.php",
    { action: "authenticate_session", login_id: session_id },
    function(data){
        if(data == "denied"){
            alert("denied");
            return false;
        }else if(data == "accepted"){
        alert("accepted");
            return true;
        }
    },
"text");
}

However, when the if statement invokes the athentication function, it doesn’t wait for the AJAX to complete, and always executes the ‘else’. If I add ‘return true;’ into the first line of the authentication function, before the ajax, the if statement performs as expected => alert(“You are authenticated”).

I know that the server side is performing properly, as the alert(“denied”) and alert(“accepted”) are being called as expected (but interestingly, after the if statement alerts).

How can I make my if statement wait until the authentication function has completed?

Thanks!

Answer 1

It’s not waiting because it’s an asynchronous request by default. Set the async option to false for it to be synchronous. From the docs:

By default, all requests are sent
asynchronous (i.e. this is set to true
by default). If you need synchronous
requests, set this option to false.
Note that synchronous requests may
temporarily lock the browser,
disabling any actions while the
request is active.