Reduce the Number of DOM Elements

The DOM, or Document Object Model, is the structure, or interface, that helps your browser understand and arrange all the elements, HTML (HyperText Markup Language), CSS, and JavaScript, etc., that make up your page. In this way, the DOM is like a tree, consisting of the headers, body elements, attributes, text, etc. When you run a website speed test, one of the suggestions you might see is to reduce the number of DOM or HTML elements. Obviously, the more elements you have on your page, the more time it takes to process all those elements, resulting in load time delays and additional memory consumption.

If you receive the suggestion to reduce the number of DOM elements, it is probably because your web page has over 1,500 HTML elements or have gone over 32 nodes. That is typically the threshold web performance tools set to trigger the warning. Before trying to resolve the warning, it is best to understand which specific elements may be contributing more to this than others. For example, plugins, chat widgets, bad coding, or even stylized and formatted text from a WYSIWYG editor, are some of the elements that cause excessive DOM size. Additionally, sometimes pages are too big, so splitting content out on multiple pages might be a better solution. Whatever it may be, review accordingly and try to optimize where possible.