Updating information on-screen?

JF1980

I don't think there is a reasonable way to do what I would like, but I thought I would ask for suggestions anyway as you never know!

I am creating a checklist for our department which consists of checks which are carried out roughly every hour. Is there a way so that if one user selects that he has carried out a check (clicks on a submit button which sets a flag in the database), then for the other users who may have the checklist page open, the page refreshes and shows that as checked.

The obvious way to pull it off would just be to have the page automatically refresh every 10 seconds or so, but this looks messy (screen reloading / flickering) and will also greatly increase the load on the webserver and database.

Any ideas? It must be possible as our call logging system is built with PHP and if someboy logs a call to yourself, then the call is added to your call list on your screen! How I don't know!😕

eoghain

Well if you have a system already writtin in PHP that works why don't you review the code and see what it does?

Other than that I don't have any suggestions. HTML/HTTP is a stateless environment so once a page is displayed the communications link ends.

Mega

yup, there's noway you could do it in PHP because it can't communicate with HTML or the browser (in this way at least)

are you certain ur other thing is coded in PHP, because i highly doubt that it is?

mrmufin

If you put the application into a frameset, you can have just the frame which contains the current checklist data refresh on a timely interval. This could avoid at least some flicker.

I believe there are ways to make a refresh meta tag so that data is only re-sent from the server if it's content has changed... Perhaps by looking at some 'chat' server scripts one could figure if I'm kinda sorta somewhat on the mark here...

Mega

it can't be done using PHP alone

JF1980

Well Im 100% sure that they use PHP. Maybe they have some other technology along side it to do this, but they definatly use PHP as their main structure.

No I can't just look to see how they have done it, although PHP it's not open source.

Yes I know how HTTP / HTML works so I know that in theory it is not possible, but I also know it has been done!😕

sarahk

Not too hard, have a hidden iframe with some javascript. Have an onload event which calls a function on the parent page to take info from the iframe and update the parent page.

Then have a metarefresh on the hidden iframe to recall itself after x seconds and the cycle repeats with no flicker!

Don't worry too much about the serverside only approach, no system is complete without a bit of both server and client side code.

JF1980

I can see what your saying, but this sounds kind of complicated! Not sure that I have the ability.

the_Igel

there's no way really to make it easy 🙂
for sure you need smth autorefreshing, e.g. iframe, that will keep track of what's going on at server.
And then you'll need to get new data at times - either reloading the whole page, or an iframe, or refreshing embedded xml...
for lesser traffic & server load you have to pay more efforts 🙁