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phpxmlajaxdrop-down-menucascadingdropdown

AJAX, PHP, XML, and cascading drop-down lists

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!

Solution

  • 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