Question

What PHP libraries would you recommend to implement the following:

• Three dependent drop-down lists
• Three XML data sources
• AJAX-based

Essentially, I’d like to create an XML database and wire up a form that allows the user to select three different dependent parameters:

1. User clicks Region
2. User clicks District (filtered by Region)
3. User clicks Station (filtered by District)

Even though I would like to use PHP and XML, the general problem is:

• One XHTML form
• Three dependent, cascading drop-down lists
• Three flat files (no relational database) for the list data

The solution must be efficient, simple, reliable, and cross-browser.

What technologies would you recommend to solve the problem?

Thank you!

Answer 1

I’d say jQuery and the Autocomplete plugin.

• make three conventional text boxes and enhance them with autocomplete()
• each one requests data from the server as the user types, via AJAX GET requests
• the server sends back the matching data as line-based text, which in turn the autocomplete plugin uses to display a list of options
• hook up an handler for the result event of the dropdowns, storing the selected option.
• the second textbox would require the first to be set and so on
• each textbox requests data from the server including all previously selected options so the server can find the right data
• the server works with DOMDocument and DOMXPath to get the data, the autocomplete plugin has built-in client side caching do ease load on the server