I have implemented a basic image slideshow on my website using a simple Javascript function. The function runs every 5 seconds to update the CSS "background-image" property of a div element. While it is functional, I've noticed that each time the function runs, it contacts the server to check if the image is in the cache, resulting in a 304 code response from the server.
Given that the images are already present elsewhere on the page and should therefore be cached upon initial loading of the website, this constant verification seems unnecessary. Below is a snippet of the code showcasing how the image URL is extracted directly from an img element:
function update(img) {
var slideshow = document.getElementById("slideshow");
slideshow.style.backgroundImage = 'url("' + image + '")';
}
function advance() {
var img = document.getElementsByClassName("slidesource")[index].src;
update(img);
index++;
}
var index = 0;
advance();
setInterval(advance,5000);
Is there a way to update the CSS property without triggering the browser to verify whether the images are in the cache?
This validation process consumes internet data (approximately 1.5kB per request), and can disrupt the slideshow functionality if there is no internet connection, even though the images are already cached.