CODEWITHSUNDEEP
javascriptcallback
John
John

Reputation: 45

Javascript callbacks - passing variables to them

I can't get the following code to work. Assume that the ajax call works, and msg['username'] is preset to 'john'. I think I am getting confused with how to pass variables to my callback. Edit: I think my main confusion was how to get the 'msg' variable out of Ajax. It looks like Ajax has a 'hard wired' success method which is pretty much compulsory to use if you want to subsequently use the data from the ajax query- and that method is the only one that can access the result of the ajax call. Here's the code:

<script>
   $(document).ready(function(){
        function freedome(horace){
           $.ajax({
               url: "RESPONDERdetails.php",
               type: "GET",           
               dataType: "json",
               data:{thing:31}
           });    
           horace(msg);
        } 

        function callbacker(msg){
            alert("I am callback");
            name = msg["username"];
            alert(name);
        }

        freedome(callbacker(msg));
        });
</script>

Upvotes: 0

Views: 55

Answers (1)

gen_Eric
gen_Eric

Reputation: 227220

You just want to use freedome(callbacker);. In JavaScript, functions can be treated like variables. So, all we need to do is pass the function itself as a parameter.

This makes horace into a function, so that when you do horace(msg);, callbacker will be called with msg as a parameter.

Also, msg is never declared anywhere in your example and your horace(msg); will run before the AJAX call is done. You need use the AJAX call's callback here.

$(document).ready(function(){
    function freedome(horace){
        $.ajax({
            url: "RESPONDERdetails.php",
            type: "GET",           
            dataType: "json",
            data:{thing:31},
            success: function(msg){
                horace(msg);
            }
        });
    } 

    function callbacker(msg){
        alert("I am callback");
        name = msg["username"];
        alert(name);
    }

    freedome(callbacker);
});

Upvotes: 1

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