How to Detect Scrollbar Visibility in JavaScript?

Inspecting Scrollbar Visibility

In pursuit of dynamically adapting web elements to content length, the question arises: how can we verify the presence or absence of a vertical scrollbar within a given element?

The jQuery example provided highlights the need for such a check: the script seeks to differentiate between elements with abundant content, visible scrollbar, and those with limited content. Here's an effective solution:

<code class="js">(function($) {
    $.fn.hasScrollBar = function() {
        return this.get(0).scrollHeight > this.height();
    }
})(jQuery);</code>

The plugin hinges on comparing the element's scroll height (the full content height) and its visible height. If the scroll height exceeds the visible height, a scrollbar is likely present.

Usage is straightforward:

<code class="js">$('#my_div1').hasScrollBar(); // Returns true if vertical scrollbar is visible, false otherwise.</code>

This approach has been tested and works across Firefox, Chrome, and Internet Explorer versions 6, 7, and 8. However, it falters when applied to the tag.

An alternative solution using client height is also presented, addressing the issue of vertical scrollbars appearing alongside horizontal scrollbars:

<code class="js">return this.get(0).scrollHeight > this.get(0).clientHeight;</code>

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