Why does $('#id') return true if id doesn't exist?

Question

I always wondered why jQuery returns true if I\'m trying to find elements by id selector that doesnt exist in the DOM structure.

Like this:

Answer 1

It returns true because to Javascript it is a defined object therefore not false, and jQuery will always give you a new object regardless of whether the element is found or not - however the array length will be zero, e.g.

$("span").length

If you have no , this will be zero, but it could be 1 or more.

You can write your own plugin to avoid repeated if statements as a Jquery plugin, like I did for this one. It's fairly easy to do:

(function($)
{
        /* Checks if a jQuery object exists in the DOM, by checking the length of its child elements. */
        $.fn.elementExists = function()
        {
                ///     

                ///     Checks if a jQuery object exists in the DOM, by checking the length of its child elements.
                ///     
                ///     
                return jQuery(this).length > 0;
        };
})(jQuery);

Usage:

if ($("#someid").elementExists())
{

}