How Can I Preload CSS Background Images to Avoid Delayed Appearance?

Preloading CSS Images

To address the issue of delayed appearance of CSS background images in a toggled contact form, it is crucial to preload these images effectively. One method to achieve this involves using CSS alone.

The following code snippet demonstrates how to preload CSS images using a random element (here, the element) as a target:

body::after {
  position: absolute;
  width: 0;
  height: 0;
  overflow: hidden;
  z-index: -1; /* hide images */
  content: url(img1.png) url(img2.png) url(img3.gif) url(img4.jpg); /* load images */
}

In this code, the ::after pseudo-element is employed to load multiple images simultaneously. By adjusting the position and z-index properties, these images are kept hidden, preventing them from rendering on the webpage. As a result, when the containing div is toggled, the images are already loaded and appear instantaneously.

For demonstration purposes, see the following:

<!-- Example usage -->
<div onclick="toggleDiv()">Toggle Me</div>

<div>

Additionally, it is recommended to use sprite images to minimize HTTP requests and ensure that the images are hosted on a server that supports HTTP2. This approach improves overall performance and guarantees a seamless user experience.

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