How to Solve Excessive DOM Size Issues in Your Shopify Theme

By Tony Ng.
June 19th, 2024

How to Solve Excessive DOM Size Issues in Your Shopify Theme

Understanding the Problem: Excessive DOM Size

Excessive DOM size is a common issue faced by many website owners. It refers to the excessive number of elements in the Document Object Model (DOM) of a webpage. While it might seem harmless, a large DOM can significantly impact your website's performance, leading to higher memory usage, longer style calculations, and costly layout reflows.

What is DOM?

The Document Object Model (DOM) is a tree-like structure that represents the elements on a web page. Each HTML tag is a node in this structure, and the nested tags form its branches. In simpler terms, the DOM is a representation of the web page that JavaScript can interact with.

Why Excessive DOM Size is Problematic

Increased Memory Usage: A large DOM consumes more memory, which can slow down your website.
Longer Style Calculations: The browser takes longer to calculate styles for a large number of elements, leading to delays in rendering the page.
Costly Layout Reflows: When the DOM changes, the browser has to recalculate the positions and geometries of elements, which can be a performance bottleneck.

Causes of Excessive DOM Size in Shopify Themes

1. Too Many Sections

Shopify themes often come with multiple customizable sections. While these sections provide flexibility, they can also bloat the DOM if overused.

2. Apps Injecting Content

Many Shopify apps inject additional HTML and scripts into your webpage. While useful, these can significantly increase the DOM size.

3. Complex Templates

Some themes come with complex HTML structures and nested elements, contributing to a larger DOM size.

How to Identify Excessive DOM Size in Your Shopify Theme

Using PageSpeed Insights

Google’s PageSpeed Insights tool is an excellent way to identify issues related to excessive DOM size. Simply enter your website’s URL, and the tool will provide a detailed report highlighting the number of DOM elements and other performance metrics.