Michael Schnell wrote:
On 11/28/2013 04:39 PM, Michael Van Canneyt wrote:
These days it is very easy to make a very responsive web gui.
"Responsiveness" (the program reacts to user input) is not the problem I
meant to describe but the ability of the program to issue "state"
messages spontaneously.
This is hampered by the missing symmetry of the http protocol: The
client needs to poll for such "reverse" messages.
It appears that around 50% of our external network traffic is caused by
a colleague who leaves a significant number of browser windows open each
with Javascript which periodically polls for server-side updates.
Almost anything is better than getting tarred with that brush.
This can partly be improved by techniques like "comet" that leave a http
protocol open in a somewhat "non-standard" way. But AFAIK, this does
result in certain problems.
That goes back to some of the earliest Netscape versions, IIRC it was
originally used to update images periodically. While attractive, this
sort of thing can turn into a nightmare if the browser on an end user's
system leaks memory until an entire page (i.e. not just part of the DOM
describing the page) is forcibly reloaded- BTDT.
--
Mark Morgan Lloyd
markMLl .AT. telemetry.co .DOT. uk
[Opinions above are the author's, not those of his employers or colleagues]
--
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