Why Isn't My Dynamically Loaded Image Updating Without a Page Reload?

Troubleshooting: Image Not Updating Dynamically

When accessing a link that provides a new image each time it is requested, you may encounter an issue where an image loaded in the background fails to update on the page unless you reload the page.

The code below illustrates the issue:

var newImage = new Image();
newImage.src = "http://localhost/image.jpg";

function updateImage()
{
    if(newImage.complete) {
        document.getElementById("theText").src = newImage.src;
        newImage = new Image();
        number++;
        newImage.src = "http://localhost/image/id/image.jpg?time=" + new Date();
    }

    setTimeout(updateImage, 1000);
}

In this scenario, the image is not updated on the page even though the request headers indicate that caching is disabled:

HTTP/1.x 200 OK
Cache-Control: no-cache, must-revalidate
Pragma: no-cache

Solution: Cachebreaker

To force a refresh of the image, add a cachebreaker to the end of the URL:

newImage.src = "http://localhost/image.jpg?" + new Date().getTime();

By appending the current timestamp, you ensure that the browser will retrieve the image from the server instead of using the cached version. This technique will allow the image to update dynamically on the page as expected.

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