How do I pass function as a parameter in javascript

Question

I have a pop up dialog box and I am trying to make it as dynamic as I can so I can send to it any function I want. I wanted to create a callback function so I can pass any function I want and it will do whatever I need on my object (in this example just print something for testing it.

here is what happens when the pop up is being called:

function DisplayPopUp(obj, callback) {


    //On Action Clicked
    $('#actionButton').click(function(e){
       e.preventDefault();
       callback(Obj);
    });
}

And here is the function that activates the PopUp function

$('.delete').click(function(){
    var obj="something something";
    DisplayPopUp(obj,function(){console.log('going to delete');});
});

Somehow that doesn't work and I get from firebug this error:

Obj is not defined

Clearly I do not transfer my function right - how should I do it?

Actual upvotes for a capitalisation typo, and downvotes for this. Silly site! — Lightness Races in Orbit
– Lightness Races in Orbit, Commented Dec 18, 2011 at 16:37

BZink · Accepted Answer · 2011-12-18 16:35:45Z

2

You're calling callback(Obj) but your variable name is obj. Check your case.

answered Dec 18, 2011 at 16:35

BZink

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Comments

pholser · Accepted Answer · 2011-12-18 16:35:40Z

1

When you invoke the callback in DisplayPopup(), pass the parameter obj, not Obj.

answered Dec 18, 2011 at 16:35

pholser

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Comments

Lightness Races in Orbit · Accepted Answer · 2011-12-18 16:36:54Z

1

Well, Obj is not defined. It should be obj.

The first thing you should do when you get an error message is to read it. :)

answered Dec 18, 2011 at 16:36

Lightness Races in Orbit

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Comments

jfriend00 · Accepted Answer · 2011-12-18 16:48:27Z

1

I see multiple possible issues with this code:

First, the case of Obj is wrong. It should be this:

function DisplayPopUp(obj, callback) {

    //On Action Clicked
    $('#actionButton').click(function(e){
       e.preventDefault();
       callback(obj);
    });
}

But, second I don't think you're using event handlers properly. You're calling DisplayPopup from a click handler. But, in that click handler, you're installing another click handler on another object. Is that really what you want to do? Unless you've left a bunch of code out of here that creates/destroys actionButton or unbinds click handlers, you can easily end up with multiple click handlers on #actionButton each time a delete button is clicked.

edited Dec 18, 2011 at 16:48

answered Dec 18, 2011 at 16:38

jfriend00

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8 Comments

Lightness Races in Orbit Over a year ago

The handlers are on different elements... If I had to guess, I'd say he's implementing an "are you sure?" box.

jfriend00 Over a year ago

I know they are on different elements. But assuming that '.delete' can be clicked more than once, they will end up with multiple click handlers on #actionButton as a new handler is attached everytime it's called. It's possible that this is handled by the rest of the code, but since we can't see that, I thought I should mention it as a possible issue.

Lightness Races in Orbit Over a year ago

I'm going to go ahead and assume that #actionButton is created in the gap in DisplayPopUp.

jfriend00 Over a year ago

@TomalakGeret'kal - As you say, that's just an assumption.

Lightness Races in Orbit Over a year ago

You could also call it an educated guess ;)

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