How Can I Dynamically Change CSS :hover Properties with JavaScript?

Change CSS :hover Properties Dynamically with JavaScript

It is intuitive to think we can manipulate CSS :hover properties with JavaScript via the familiar properties object. However, :hover is a pseudo-class that applies styles to an element only when the mouse hovers over it. This means it cannot be accessed directly through the properties object.

To manipulate :hover properties with JavaScript, one must go beyond the properties object and venture into manipulating the stylesheet itself. This can be achieved in several ways, each with its pros and cons:

Direct CSS Modification:

document.getElementsByTagName("style")[0].innerHTML = 'table td:hover{ background-color: #00ff00 }';

While direct modification can be quick, it overwrites the existing stylesheet, potentially leading to unexpected consequences.

Creating a New Stylesheet:

var css = 'table td:hover{ background-color: #00ff00 }';
var style = document.createElement('style');
style.type = 'text/css';
style.appendChild(document.createTextNode(css));
document.getElementsByTagName('head')[0].appendChild(style);

This method allows for more controlled styling changes by creating a new stylesheet that only includes the desired :hover modifications. However, it also brings the overhead of maintaining multiple stylesheets.

Appending a New Rule to the Current Stylesheet:

if (style.styleSheet) {
    style.styleSheet.cssText += 'table td:hover{ background-color: #00ff00 }';
} else {
    style.appendChild(document.createTextNode('table td:hover{ background-color: #00ff00 }'));
}

This approach extends the current stylesheet by appending a new :hover rule. It offers a balance between direct modification and creating a new stylesheet.

Ultimately, the method chosen depends on the complexity of the required changes and the overall website architecture. Dynamically modifying :hover properties with JavaScript provides flexibility in creating interactive effects.

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