How to Defer Large CSS File Loading for Improved Website Performance?

Optimizing CSS Delivery: Deferring Large CSS File Loading

In the pursuit of optimizing website performance, one common technique involves deferring the loading of large CSS files until after the page's initial content has loaded. This strategy helps reduce page rendering time and improve perceived performance.

Deferred Loading with jQuery

If you're comfortable using jQuery, you can implement deferred CSS loading using the following code snippet:

<code class="javascript">function loadStyleSheet(src) {
    if (document.createStyleSheet){
        document.createStyleSheet(src);
    }
    else {
        $("head").append($("<link rel='stylesheet' href='"+src+" />"));
    }
};</code>

Simply call this function within your $(document).ready() event handler to defer loading the CSS file.

Alternative Method

Alternatively, if you prefer to avoid using jQuery, you can manually create a link element and append it to the document head. Here's an example:

var link = document.createElement("link");
link.rel = "stylesheet";
link.href = "large.css";
document.head.appendChild(link);

No Javascript

Note that loading CSS files after page load requires modifications to the HTML code. If JavaScript is disabled in the browser, the deferred CSS file will not be loaded. Therefore, it's crucial to inline critical CSS within the HTML or consider alternative optimization techniques.

The above is the detailed content of How to Defer Large CSS File Loading for Improved Website Performance?. For more information, please follow other related articles on the PHP Chinese website!