How can I dynamically change CSS class rules using jQuery without touching the DOM?

Modifying CSS Class Rules Dynamically with jQuery

Question 1: Changing Class Rules on the Fly

To change the font size of a CSS class named ".classname" using jQuery, without adding inline CSS or directly manipulating the DOM, follow these steps:

<code class="javascript">// Get the CSS stylesheet
var styleSheet = document.styleSheets[0];

// Loop through the CSS rules within the stylesheet
for (var i = 0; i < styleSheet.cssRules.length; i++) {
    // Check if the current rule is for the ".classname" class
    if (styleSheet.cssRules[i].selectorText === ".classname") {
        // Set the new font size for the rule
        styleSheet.cssRules[i].style.fontSize = "16px";
    }
}</code>

Question 2: Saving Class Changes to a File

To save the modified CSS class rules to a file, you'll need to create an Ajax POST request to the server.

<code class="javascript">// Build a string containing the updated CSS declarations
var updatedCSS = "";
for (var i = 0; i < styleSheet.cssRules.length; i++) {
    updatedCSS += styleSheet.cssRules[i].selectorText + " {\n";
    for (var j = 0; j < styleSheet.cssRules[i].style.length; j++) {
        updatedCSS += "    " + styleSheet.cssRules[i].style[j] + ": " + styleSheet.cssRules[i].style.getPropertyValue(styleSheet.cssRules[i].style[j]) + ";\n";
    }
    updatedCSS += "}\n";
}

// Send the updated CSS to the server
$.ajax({
    type: "POST",
    url: "/save-css",
    data: { updatedCSS: updatedCSS }
});</code>

On the server-side, create a script to save the received updated CSS to a file.

Additional Notes

• The first approach doesn't affect the external CSS file but only modifies the CSS rules in memory, so it will not persist after the page refresh.
• For cross-browser compatibility, consider using a jQuery plugin that simplifies CSS rule manipulation.

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