Check if src exists on the page

Question

I have a script that generates img tags, and i want to make sure the same img isn't being made twice. This is the script i tried to create:

var included = 0;
var src = "";

jQuery.fn.checkCard = function() {
    if ($("#L_S_Inner").find($('img').attr(src))){
        included = 0;
    } else {
        included = 1;
    }
}

However it doesn't work. Not sure what i'm doing wrong here...

It's framed this way so that i can just check the variable 'included' in my img creation script.

EDIT

Added the img creation script:

$('#Results a').live('dblclick', function() {
    src = $(this).attr('href');
    getC = $(this).attr('class');
    checkCard();

    if (!(checkCard)) {
            $(this).parent().append($('<img />', {'src': src, 'class': 'DCT ' + getC + ''}));
    }
});

Answer 1

Several problems here. First off, despite your explanation, I don't see the need for the global variable. It's ugly and dangerous practice - it should be the return value of the function, unless you have damned good reasons not to do it that way.

Second, the as @sosborn says, the function does not have an input parameter - the src is either another global (that you haven't shown), or the code just can't work.

Next, inside find there should be a selector, not a jQuery object, and inside attr there should be an attribute name (thus, a string "src"), not a value (presumably src contains something like http://...).

Also, why make it into a jQuery plugin?

Literal solution of the problem, I'd do this way:

var checkCard = function(src) {
    return !!($('#L_S_Inner img[src="' + src + '"]').length);
}

A better yet solution is to remember what images you create by tracking them manually - much faster.

var included = [];
// ...
// when you make an image
included[src] = true;
// ...
// when you want to know if it is there
if (included.hasOwnProperty(src)) // ...

UPDATE: With the creation code posted, let me rewrite the second solution:

var included = [];
$('#Results a').live('dblclick', function() {
    var src = $(this).attr('href');
    var getC = $(this).attr('class');

    if (!included.hasOwnProperty(src)) {
        $(this).parent().append($('<img />', {'src': src, 'class': 'DCT ' + getC + ''}));
        included[src] = true;
    }
});

By the way, notice the vars I added to your inner variables. Declare your variables, it's good for health.