How Can I Dynamically Modify and Remove CSS Class Definitions with JavaScript?

Modifying and Removing CSS Class Definitions Dynamically

Adding CSS classes at runtime is a known JavaScript manipulation, but extending its functionality to modifying or removing existing class definitions may seem daunting. This article addresses this challenge by exploring ways to achieve these operations programmatically.

Changing CSS Class Definitions

To edit a CSS class definition, follow these steps:

1. Access the document's style sheets using document.styleSheets.
2. Loop through the cssRules property of each style sheet to find the rule you wish to modify.
3. Once the rule is found, update its style property using setProperty.

For example, to modify the font size of the .menu class:

let styleSheet = document.styleSheets[0];
let rule = styleSheet.cssRules[1]; // Assuming ".menu" is the second rule
rule.style.setProperty('font-size', '15px');

Removing CSS Class Definitions

To remove a CSS class definition, follow these steps:

1. Locate the style sheet and rule as described in the previous section.
2. Remove the rule from the cssRules collection using deleteRule.

For example, to remove the .menu class definition:

let styleSheet = document.styleSheets[0];
let rule = styleSheet.cssRules[1]; // Assuming ".menu" is the second rule
stylesheet.deleteRule(1);

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