Finding if element is visible (JavaScript )

Question

I have a javascript function that tries to determine whether a div is visible and does various processes with that variable. I am successfully able to swap an elements visibilit

Answer 1

Let's take a second to see what .is(":visible") is doing in jQuery, shall we?

Here's a link: https://github.com/jquery/jquery/blob/master/src/css.js#L529

return !jQuery.expr.filters.hidden( elem );

where

jQuery.expr.filters.hidden = function( elem ) {
    // Support: Opera <= 12.12
    // Opera reports offsetWidths and offsetHeights less than zero on some elements
    return elem.offsetWidth <= 0 && elem.offsetHeight <= 0;
};

So, it's just checking the offset width and height of the element.

That said, and also worth noting, when jQuery checks to see if an element is hidden (i.e. like when triggering a 'toggle' event), it performs a check on the display property and its existence in the dom. https://github.com/jquery/jquery/blob/master/src/css.js#L43