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Editorial Team
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Asked: 2026-06-10T18:59:42+00:00

Having some trouble refreshing the image, i have a script running in the background

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Having some trouble refreshing the image, i have a script running in the background updating the image and i want to display the new image every X seconds, but when i run in browser the image is not refreshed
Anyone got any ideas?

<!DOCTYPE html PUBLIC \"-//W3C//DTD HTML 4.01 Transitional//EN\" \"http://www.w3.org/TR/html4/loose.dtd\>
<html> 
    <head>
        <meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1\>
        <title> Title </title> 

        <script>
            var image;
            var imgBase="images/test.jpeg"
            function count(){
                image.src=imgBase;
            }

            function init(){
                image = document.getElementById("image");

                if( image ){
                    setInterval("count()",1000);
                }
            }

            window.onload = init;
        </script>
    </head>
    <body>
        <img src="images/test.jpeg" id="image">
    </body>
</html>

The web-application has the following directory tree ..

.
├── Home.jsp
├── images
│   ├── test.jpeg
├── META-INF
│   └── MANIFEST.MF
├── style.css
└── WEB-INF
    ├── classes
    │   └── test
    │       └── my
    │           └── new
    │               └── package
    │                   └── Test.class
    ├── lib
    └── web.xml
    9 directories, 10 files

Web console does not show any errors retriving image, but it does not refresh?
[00:53:15.896] GET http://host:8085/Servlet/Display?config=L1 [HTTP/1.1 200 OK 2ms]
[00:53:16.419] GET http://host:8085/Servlet/images/test.jpeg [HTTP/1.1 200 OK 2ms]

Appreciate any help, thanks!

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1 Answer

  1. Editorial Team

    The browser is showing the image from the browser cache.

    A workaround is to request the image using an unique request parameter (e.g. a timestamp), so that the browser is forced to actually send a fresh new HTTP request instead of showing the image from the browser cache.

    function count(){
    image.src = imgBase + "?" + new Date().getTime();
}

    Note that this concrete problem has nothing to do with servlets. Even more, putting HTML code straight in a servlet class is a poor practice. HTML code belongs in a JSP file (and Java code in a servlet class).

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