I have an Ajax request waiting for response from another process.

function test() {
    var flag = 0;
    while (flag === 0) {
        $.ajax({
            url: "cs/CheckForProcess",
            async: false,
            success: function(data) {
                if (data !== 'NotReady') {
                    $('#results').html(data);
                    flag = 1;
                } else {
                    $('#results').html('<h1>Processing...</h1>');
                    setTimeout(function() {
                    }, 6000);
                }
            }
        });
    }
}

the problem is that the setTimout isnt working although i see in debug mode that the else condition is executed.

EDIT: i want the next ajax request to be sent only 6 seconds after validating the process is not ready.

what am i missing? Thx.

I have an Ajax request waiting for response from another process.

function test() {
    var flag = 0;
    while (flag === 0) {
        $.ajax({
            url: "cs/CheckForProcess",
            async: false,
            success: function(data) {
                if (data !== 'NotReady') {
                    $('#results').html(data);
                    flag = 1;
                } else {
                    $('#results').html('<h1>Processing...</h1>');
                    setTimeout(function() {
                    }, 6000);
                }
            }
        });
    }
}

the problem is that the setTimout isnt working although i see in debug mode that the else condition is executed.

EDIT: i want the next ajax request to be sent only 6 seconds after validating the process is not ready.

what am i missing? Thx.

• javascript
• jquery
• ajax
• sleep

• There is nothing in your setTimeout function. What are you trying to do there? – putvande Commented Nov 3, 2013 at 17:50
• just sleep....isn't that the standard syntax for sleeping? – Danny Valariola Commented Nov 3, 2013 at 17:52
• setTimeout is an async function. It does not pause your script. Your script will continue to run (and 6000ms later your setTimeout callback function will execute. – jaredrada Commented Nov 3, 2013 at 17:52
• Can you tell us exactly what your trying to do ? – The Alpha Commented Nov 3, 2013 at 17:55
• What exactly are you trying to do? – putvande Commented Nov 3, 2013 at 17:55

3 Answers 3

setTimeout is an async function. It does not pause your script. Your script will continue to run (and 6000ms later your setTimeout callback function will execute).

You could consider using setInterval to keep checking for your other condition to be true.

You could probably remove async:false by keeping track of your server response elsewhere. Once you have a successful callback then you should cancel the interval.

function test() {
    var timerId = 0,
    timerId = setInterval(function(){
        $.ajax({
            url: "cs/CheckForProcess",
            success: function(data) {
                if (data !== 'NotReady') {
                    $('#results').html(data);
                    clearInterval(timerId);
                }
            }
        });
    }, 6000)
}

Javascript does not have the ability to sleep (e.g. suspend or block javascript execution) using setTimeout.

A setTimeout() schedules a function to run sometime in the future and other javascript just happily keeps running during that time.

What you should do is use setTimeout() to schedule the next run of your ajax function if the data was not yet ready. So, when there is no data ready, you schedule the next ajax call for 6 seconds from now, but when you do get the data, you just process the data and you're done.

In addition, you really don't want to use async: false because that freezes the browser (doesn't allow any other processing to occur) during the ajax call. This same operation can be written to leverage the asynchronous nature of ajax and allow you to still solve your problem, but allow other processing to continue in the browser with no browser blocking. This requires asynchronous programming techniques.

You can do so like this:

function test() {

    function runIt() {
        $.ajax({
            url: "cs/CheckForProcess",
            async: true,
            success: function(data) {
                if (data !== 'NotReady') {
                    $('#results').html(data);
                } else {
                    // if data not ready yet, then put up some progress
                    // and call this again in 6 seconds
                    $('#results').html('<h1>Processing...</h1>');
                    setTimeout(runIt, 6000);
                }
            }
        });
    }

    // start the first iteration
    runIt();
}

The setTimeout function takes a function to execute after the timeout. You are passing an empty function. So, after 6 seconds, that empty function is executing - and obviously not doing anything.

I think you are expecting setTimeout to delay the execution of other scripts on your page. This is not the case, as setTimeout delays and executes the supplied callback function in a new thread (not blocking other execution on your page).

If you are trying to do something after 6 seconds, just supply the code inside of the function() {} code you have. Eg:

setTimeout(function() {
    $.ajax(...);
}, 6000);

or

setTimeout(runIt, 6000);

Links:
setTimeout documentation (mozilla)
Related SO question