Posted by J.O. Aho on 05/10/07 20:20

Dave Boland wrote:
> I'm doing some work on a data acquisition system for temperature
> sensors. The displayed readings don't change much over time, so what I
> would like to do is to force a page refresh only when the data changes
> by 5% or more, or when the temperature is over a limit.

JavaApplet, see
http://java.sun.com/docs/books/tutorial/uiswing/components/applet.html


> So far my options seem to be frequent page refreshes using a meta tag,
> or using Java.

I think you mean JavaScript, which isn't at all the same thing as Java.
See this article: http://www.htmlgoodies.com/beyond/javascript/article.php/3470971


> The meta tags are a fixed time interval and may be too
> frequent (or not frequent enough)

The only way to make HTML to load a page is to let an user load a page or use
meta tag to reload in an interval, or send a http-header that tells the
browser to reload the page after a time interval or use javascript to count
down time to force the browser to reload the page.

A server can't just send a page to someone without request (of course it
could, but no browser would get the data).


--

//Aho

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