Javascript Function Call have different behaviour compared to run by console in web browser

Question

i have this code:

function foo(){
    var x = $.getJSON('./someFileName.txt',function(data){});
    var y = x.responseText;
    console.log(y);
}

when i called it via browser console (firefox), it give me undefined for the console log result.

But, when i just copy, paste and, run the foo() function body line by line in my browser console, it gives me a result which is a string.

Can anyone enlighten me why this behaviour happens? I suppose it has something to do with the jquery call but i am not sure.

Thanks!

Answer 1

You need to place the second and third lines of your function inside the callback like this:

function foo(){
    $.getJSON('./someFileName.txt',function(data){
    var y = data.responseText;
    console.log(y);
    }); 
}