How Can I Dynamically Retrieve CSS Class Styles Using JavaScript or jQuery?

How to Dynamically Retrieve CSS Class Styles Using JavaScript/jQuery

In web development, styling is often defined using CSS classes. To modify an element's style based on a CSS class, you can leverage JavaScript or jQuery.

Retrieving Styles with jQuery

jQuery provides a convenient method to access style attributes from CSS classes:

$(element).css(styleAttribute);

For instance, to obtain the color of an element with the class "highlight":

var color = $(element).css("color");

Alternate Method Using a Function

Another approach is to use a function that traverses the stylesheets in the document:

function getStyleRuleValue(style, selector) {
  // Iterate through style sheets
  for (var i = 0; i < document.styleSheets.length; i++) {
    var sheet = document.styleSheets[i];

    // Iterate through rules in the current sheet
    for (var j = 0; j < sheet.cssRules.length; j++) {
      var rule = sheet.cssRules[j];

      // Check if the rule matches the selector
      if (rule.selectorText.includes(selector)) {
        // Return the requested style
        return rule.style[style];
      }
    }
  }

  // No matching rule found
  return null;
}

Usage:

var color = getStyleRuleValue("color", ".highlight");

This function can retrieve styles from both inline and external stylesheets, but it's limited to same-domain external sheets.

Example Usage

Consider the following CSS class:

.highlight { 
    color: red; 
}

To animate an object's color to match the "highlight" class:

$(this).animate({
    color: getStyleRuleValue("color", ".highlight")
}, 750);

This approach allows you to dynamically change the CSS color and have the animation respond to those changes, providing a seamless and consistent user experience.

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