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

Modifying and Removing CSS Class Definitions Dynamically

Manipulating CSS class definitions at runtime allows for dynamic control over the visual appearance of web elements. This can be useful for customizing the user experience based on specific conditions or user preferences.

Modifying CSS Class Definitions

To modify an existing CSS class definition, you can use the document.styleSheets property to access the stylesheet rules. Each rule can then be updated using the rule.style property.

For example, to change the font size of the .menu class to 10px:

// Get the stylesheet
const stylesheet = document.styleSheets[0];

// Find the .menu rule
const rule = Array.from(stylesheet.cssRules).find(r => r.selectorText === '.menu');

// Change the font size
rule.style.setProperty('font-size', '10px', null);

Removing CSS Class Definitions

To remove a CSS class definition, you can use the deleteRule method of the document.styleSheets object.

For example, to remove the .menu class definition:

stylesheet.deleteRule(stylesheet.cssRules.length - 1); // Assuming .menu is the last rule

Alternatively, you can set the display property of the rule to none to effectively hide elements that use that class.

rule.style.setProperty('display', 'none', null);

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