pass a call by reference as call by value

Question

I've been using this code to move ImageId to jCrop

But _ImageId variable is given by reference.

How can I give _ImageId variable to the jCrop by value?

    var _ImageId = 0;

    $(document).ready(
    function(){    
        $('.page .image').attr("id", function(){  
        _ImageId = $(this).attr("id");
        return $(this).attr("id");
    }).Jcrop({
        ImageId : _ImageId,  // my problem is here , when _ImageId change , all of them will change 
        onSelect: Page_ImageSelected
    });      
}

All javascript values are passed by value, even if they are references to objects. — Bergi, Dec 21 '12 at 11:23

score 1 · Answer 1 · answered Dec 21 '12 at 11:23

1

Your code is a little ... "weird".

Maybe you should try something like that :

$(document).ready(function() {
    $('.page .image').each(function() {
        var element = $(this);
        element.Jcrop({
            ImageId : element.attr('id'),
            onSelect: Page_ImageSelected
        });
    });
});

Javascript use a "by value" call when you are using "simple" types like number, integer, float, string, boolean ...

The problem here is your code.

answered Dec 21 '12 at 11:23

Magus

14,796
3
36
51

even I think your code should works , but it do not work anyway , evern It do not run until var element = $(this); – Ata Dec 21 '12 at 11:34
So maybe your selector `.page .image` is wrong. But i can't tell without your html code. – Magus Dec 21 '12 at 11:36

score 0 · Answer 2 · answered Dec 21 '12 at 11:25

0

You already do pass the _ImageId by value, the JCrop method will receive an object whose ImageId property is 0 (or the value assigned in the attr callback) and will not change when _ImageId is changed.

answered Dec 21 '12 at 11:25

Bergi

630,263
148
957
1,375

When do it change, what do you think changes it? Of course the property might change, but not from assignments to `_ImageId` – Bergi Dec 21 '12 at 11:52

pass a call by reference as call by value

2 Answers2