CODEWITHSUNDEEP
javascriptjquerycallbackready
Chris
Chris

Reputation: 200

How to check if javascript function is ready/done (jQuery)

I am working on a learning planner which gets its data (languagekeys, tasks, activities, etc.) from a database. Because I need a JSON string, I encode it with json_encode to work with it in JavaScript. I have a different function (for keys, tasks, activities, etc.) which gets this data and writes it into an array.

function get_tasks(start_date,end_date){

    maxsubtasks=0;
    maxtasks=0;

    $.getJSON(json_data+"?t_startdate="+start_date+"&t_enddate="+end_date, function(data) {  

        tasks=new Array();

        $.each(data.tasks, function(i,item){

            tasks[i]= new Object();
            tasks[i]["t_id"]=item.t_id;
            tasks[i]["t_title"]=item.t_title;
            tasks[i]["t_content"]=item.t_content;
            . . .

            if ( i > data.tasks.length) return false;    
            maxtasks = data.tasks.length;
            if(item.t_parent > 0){
                maxsubtasks++;
            }
        });         
    });
    return true;
}

Everything is working just fine. I need some help, because I now have to call this function in $(document).ready(). I want to build my learning planner only once the function get_tasks() is complete (the array is filled with data). Otherwise, I will get errors.

How can this be solved?

Here is what I have in $(document).ready():

if(get_tasks(first_day,last_day) && get_tmp_data()){ // If this function is done
    // This function should be fired -- just like a callback in jQuery
    init_learnplanner();
}

Upvotes: 1

Views: 16887

Answers (4)

Guffa
Guffa

Reputation: 700910

You can add a callback to the function:

function get_tasks(start_date, end_date, callback) {

Then after populating the array in the function, call the callback function:

if (callback) callback();

Now you can use the callback parameter to initialise the learning planner:

get_tasks(first_day, last_day, function() {
    init_learnplanner();
});

Upvotes: 2

Chris
Chris

Reputation: 200

Other answers haven't worked for me because I have 5 functions which use my data with $.getJSON, and I need to have collected all information to even start init_learnplanner().

After several hours of searching, I've discovered the jQuery function ajaxComplete, which works like a charm for me. jQuery tracks all ajax calls that have been fired and triggers anything assigned .ajaxComplete() when one is complete.

Upvotes: 1

AnD
AnD

Reputation: 3129

What I'm doing is usually something like this: simple, looks like beginner but it works :) :D

    <script type="text/javascript">
        var isBusy = true;
        $(document).ready(function () {
    // do your stuff here
            isBusy = false;
        });

        function exampleajax() {
            if(isBusy) return false;
            isBusy=true;
            $.ajax({
                async: true,
                type: 'POST',
                url: "???.asp",
                dataType: "jsonp",
                data: qs,
                error: function(xhr, ajaxOptions, thrownError){
                //console.log(xhr.responseText + " AJAX - error() " + xhr.statusText + " - " + thrownError);
                },
                beforeSend: function(){
                //console.log( "AJAX - beforeSend()" );
                },
                complete: function(){
                //console.log( "AJAX - complete()" );
    isBusy = false;
                },
                success: function(json){
                //console.log("json");
                }
            });
        }
</script>

hope this help you

Upvotes: 0

joni
joni

Reputation: 5482

You should be able to specify a callback in $.getJSON, which gets executed as soon the request is completed.

EDIT: You're already doing this, but why don't you just call the second code block from the end of the callback funciton in $.getJSON?

Upvotes: 1

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