jQuery: testing for existence of something

Question

Newbie alert...

I'm trying to make an educational that uses different audio players (with different ids) depending on the browser. In some cases, the div ids will be #f-FIVE, for example, or, in other cases just #FIVE. This is not something I have a lot of control over due to the audio players.

Using jQuery, I want to use the div ids to test for which audio player is being used.

In this fiddle http://jsfiddle.net/eft84/15/, I am trying (unsuccessfully) to fade out an element using an if then structure if #f-FIVE exists. Would you be kind enough to help me spot my errors.

possible duplicate of [Is there an "exists" function for jQuery](http://stackoverflow.com/questions/31044/is-there-an-exists-function-for-jquery) — Daniel A. White, Jul 19 '11 at 22:40

score 1 · Accepted Answer · answered Jul 19 '11 at 22:40

1

Here you go: http://jsfiddle.net/Paulpro/SySRb/

$('#f-FIVE').length

Will be 1 or more if there is a match (Should be exactly one since it's an id selector). If there is no match it will be 0 and evaluate to false.

answered Jul 19 '11 at 22:40

Paul

139,544
27
275
264

score 1 · Answer 2 · answered Jul 19 '11 at 22:42

1

With jQuery, you can check if the result of a selector is empty like this:

if ($("#f-FIVE").length) {
    // do something
}

answered Jul 19 '11 at 22:42

satoru

31,822
31
91
141

Thanks a lot. PaulPRo answered first so I have to give him accepted answer. – Leahcim Jul 19 '11 at 22:44

score 0 · Answer 3 · answered Jul 19 '11 at 22:55

I don't understand what the IF should do? I corrected the code below.

$(document).ready(function() {
    init();
});

function init() {
    var x = true; //#f - FIVE
    if (x === true) {
        $('#f-FIVE, #f-SIX').hide(1000);
    } else {
        return;
    }



}

jQuery: testing for existence of something

3 Answers3