Simple problem in javascript: Uncaught ReferenceError: function_name is not defined.

Question

Hello,

I have a little problem in a simple javascript app with cordova and jquery defined:

When I launch app on Javascript console I read that:

 Uncaught ReferenceError: prova is not defined.

And that is not true, I defined the function in javascript as follow:

 function onDeviceReady() {
        // Handle the Cordova pause and resume events
        document.addEventListener( 'pause', onPause.bind( this ), false );
        document.addEventListener( 'resume', onResume.bind( this ), false );
        
        // TODO: Cordova has been loaded. Perform any initialization that requires Cordova here.
        var b = document.getElementById("bottone");
        b.addEventListener('click', prova, false);
    };

    function prova() {
        $("p").hide();
    };

And then I have a lot of Uncaught ReferenceError: p is not defined while <p> is simple defined in my html as follow:

<p>Hello, your application is ready!</p> 

So my question is:

As this simple application run without problems after build, can I ignore these errors or there is a solution?

Thank you

Answer 1

Just try reordering your code this way. Defining the prova function before it's referenced:

    function prova() {
        $("p").hide();
    }

 function onDeviceReady() {
        // Handle the Cordova pause and resume events
        document.addEventListener( 'pause', onPause.bind( this ), false );
        document.addEventListener( 'resume', onResume.bind( this ), false );
        
        // TODO: Cordova has been loaded. Perform any initialization that requires Cordova here.
        var b = document.getElementById("bottone");
        b.addEventListener('click', prova, false);
    };

Answer 2

Thank you for your answer Deric,

that resolved the problem but still don't understand why these errors:

<p> is simple in html file, so why change function order resolve the problem?

And then, why I don`t have same errors with the "onPause"and "onResume" functions? The situation is like my function prova, they are defined after the "addEventListerner()"

And finally, why app can run if I had these errors?

Thank you

Answer 3

Aidoru good that your problem is solved. Now we have a question about browser engine and definitions.

Your problem does not occurs in runtime because all functions are already loaded in your window context. I think this is a IDE problem, that does not load the entire context (document, dependences, scripts) in development time.

Answer 4

Thank you Deric,

javascript debug is so different than other languages debug, not so strict rules in javascript, an error could be a "not error" and app can live with it.

Answer 5

Yes it is. And what's your conclusion? Was your question answered?

Answer 6

The problem has been solved, for the answer about how it is possibile to solve it by change functions order I think that it will remain a sort of thing without a logical answer

Thank you