Refreshing Dropdown box

RickL66

Hello, I did some searching here, and it looks like refreshing is what I need, but it seems that most posts were 2005 or older. Maybe there is a new way to do this?

I have a form that inckudes two dropdown boxes. One is Category and the other is Subcategory. To make things simple, let's say I have Fruits selected in Category. Subcategory would have a list of fruits, like Apples, Bananas, Oranges. If one changes Category to Vegtables, I want subcategory to automatically refresh with a new list, like Beans, Carrots, Peas. What is the best way to do that?

Thanks!

bpat1434

The best way is the typical onChange="this.submit()"

Another way is to utilize AJAX to add the drop-down without use of a refresh.

Unfortunately that's really the only ways that I know of. It's 10 year old technology, but hey: if it ain't broke don't fix it 😉

shamly

if the category list and subcategory list isnt that big you can load the whole thing on to a javascript array. With this you will be able to refresh the subcategory list everytime the category changes.

RickL66

shamly wrote:
if the category list and subcategory list isnt that big you can load the whole thing on to a javascript array. With this you will be able to refresh the subcategory list everytime the category changes.

Unfortunately they are big. I'll have to look into the onChange event. Does anyone have any examples?

shamly

onChange="this.submit()" basically submits the page .... by checking the vaule of the category selected you can get the list of subcategories from the DB. Just do a print_r($_POST) and look for the name you have given for the category list and the corresponding value.

Crowly

This might be helpful on the way, http://www.thesitewizard.com/archive/navigation.shtml

SoulAssassin

I think AJAX is your best option.
http://www.ajax-tutorials.com/tutorial-list

alirezaok

bpat1434 wrote:
The best way is the typical onChange="this.submit()"

Another way is to utilize AJAX to add the drop-down without use of a refresh.

Unfortunately that's really the only ways that I know of. It's 10 year old technology, but hey: if it ain't broke don't fix it 😉

what is diffrence between onChange="this.submit()" and onChange="submit(this)" ?

alirezaok

i know this is php forum but anyone knows this?

bpat1434

this is the javascript object for the current element (form). submit(this) is completely foreign to me, and it might be a custom function to submit just that element of the form via a GET query.

You have two options to go with: (1) Use ajax and submit the form to get the new contents or (2) submit the form and let PHP do the work without AJAX.

Either way, works. The question is how much time do you want to put into coding it? AJAX will take longer (especially if you don't know it) than PHP. AJAX can also be disabled by browsers so users won't get that nice update.

If all else fails, you could do a "stepping" process where the users select one item, then move to a new page to select another, then a new page to select another until they get to what they want. It's antiquated, but it can't be disabled by browsers, and it will always work.

SoulAssassin

That defies the object.
He needs the values in the form to dynamically update as choices are made.
PHP can't do this unless a form POST.

If it's that important for users to have a dynamic form, they would have to use some JAVA, and AJAX is your answer. Even if it takes a little longer to code.