Why does this if always return true?

Question

I am checking for string inside of a div element using jquery but it allways returns the if never the else even when the dom doesn't contain then $ what stupid mistake am i making?

$('.bw-switcher').on('click', function() {
    $(this).toggleClass('toggledrate', 1000);
    $('.toggledrate > .bwswitch-button:before').toggle('fast');
    $('.toggle_rates').toggle('fast');
    if ($(".deatils.dailyPrice:contains($)")) {
        $('.deatils.dailyPrice').toggle('fast');
        console.log('I am the if');
    } else {
        console.log('I am the else');
        $('.deatils.dailyPrice').toggle('fast').prepend('$');
    }
    $('.toggledrate > .bwswitch-button:after').toggle('fast');
});

Because `{}` is always equal to true. – Kevin B Aug 13 '13 at 19:44 — Kevin B, Aug 13 '13 at 19:44

score 9 · Accepted Answer · answered Aug 13 '13 at 19:45

9

Because $(".deatils.dailyPrice:contains($)") is an object and not null objects are always evaluated as true in if tests.

From the MDN :

Any value that is not undefined, null, 0, NaN, or the empty string (""), and any object, including a Boolean object whose value is false, evaluates to true when passed to a conditional statement

You probably want

if ($(".deatils.dailyPrice:contains($)").length) {

answered Aug 13 '13 at 19:45

Denys Séguret

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thank you you are completly right!! so which is the more elegant solution using length as you have suggested or size > as @esalija suggests? – vimes1984 Aug 13 '13 at 19:48
2

`size` is deprecated and [jQuery recommends length](http://api.jquery.com/size/). – Denys Séguret Aug 13 '13 at 19:48
Ok point taken answer accepted! – vimes1984 Aug 13 '13 at 19:49
Yes srry I left the comp... – vimes1984 Aug 14 '13 at 17:54

Esailija · Answer 2 · 2013-08-13T20:14:24.863

2

The jQuery function constructs a jQuery object. Objects are always considered true in a truthiness evaluation such as if.

Try this

if( $(".deatils.dailyPrice:contains($)").length > 0 )

edited Aug 13 '13 at 20:14

answered Aug 13 '13 at 19:44

Esailija

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Note that size is deprecated : http://api.jquery.com/size/ – Denys Séguret Aug 13 '13 at 19:46
@dystroy thank you, that was completely surprising and unreasonable – Esailija Aug 13 '13 at 20:14

Why does this if always return true?

2 Answers2