HTML Listeners?

[mlambert]

Hey, I was wondering if anyone knew of some functionality that PHP provides for that allows some form of HTML action listeners? I want a dynamic page to refresh values in combo boxes dependant on the value selected in one of the combo boxes. Does anyone know if this is possible?

[sarahk]

Yep, possible.

Questions which impact on design
are the new values from the database?
is the page allowed to be submitted and redrawn?
* is javascript allowed to be used?

If the page can't be submitted (and there are good reasons why that might be) then you need to use javascript to change the values of the combo box.

Now, if the values have to be obtained from the database then

• each new combination set could be added to the html when it's first created with PHP produced javascript arrays holding those combinations. Then when a choice is made the right array is found and the combo is redrawn

• you could have hidden iframes with tiny forms on them which are given the selected value and submitted. When they return they hold javascript which prompts the main form to redraw the combos.

I have a demo of iframes updating main forms which you can see at http://property.digitalrice.com/muck/example.php

[mlambert]

Thanks for your help Sarah. I thought I may need to use some client-side script language like Javascript or VBScript but was trying to see if their was some function like an onClick() in PHP. Guess not. Anyhow, thanks for your time.... m@ 🙂

[sarahk]

One of the big learning curves is knowing when serverside kicks in and when clientside is used. Sounds simple but I've seen experienced app programmers struggle with this for far longer than seems plausible.

I've got a bit of a rant at http://property.digitalrice.com/phpjavascript.php