--- title: "Tip: Minimize DOM access" shortTitle: Minimize DOM access type: tip tags: javascript,browser author: chalarangelo cover: blog_images/armchair.jpg excerpt: Increase your JavaScript code's performance when working with the DOM by leveraging this simple trick. firstSeen: 2020-11-20T09:18:55+02:00 lastUpdated: 2021-06-12T19:30:41+03:00 --- DOM operations, including accessing the DOM, are generally slow. This is usually not a problem until you have to perform many DOM operations and your JavaScript application's performance starts to suffer. A very quick trick to increase performance is to store DOM elements or their values in local variables if you plan to access them multiple times. ```js // This is slow, it accesses the DOM element multiple times document.querySelector('#my-element').classList.add('my-class'); document.querySelector('#my-element').textContent = 'hello'; document.querySelector('#my-element').hidden = false; // This is faster, it stores the DOM element in a variable const myElement = document.querySelector('#my-element'); myElement.classList.add('my-class'); myElement.textContent = 'hello'; myElement.hidden = false; ``` Note that, while this trick may come in handy, it comes with the caveat that if you later remove the DOM element and you still have it stored in a variable, the variable should be set to `null` to avoid potential memory leaks.