I recently had a requirement to implement an auto-complete input box in a dynamic form. Since I was already using jQuery, I had a look at the available plugins.

After sorting through a few, I decided on this one from Jörn Zaefferer. The only problem was, I wanted to use the wonderfully simple Zend Framework AjaxContext Action Helper to produce JSON data as my auto-complete data source. I like JSON as it’s easy to produce and easy to deal with in disparate systems (such as PHP and JavaScript). Unfortunately, Jörn’s plugin is built to work with a simple, formatted ASCII list delimited by newlines. Fortunately, he also put a lot of work into this plugin, he just hasn’t gotten around to documenting it all yet.

For this post, I’ll assume my AJAX request is for some user data out of LDAP (or a similar data store) and resembles this

    {"uid":"123","displayName":"User 123","mail":"123@example.com"},
    {"uid":"456","displayName":"User 456","mail":"456@example.com"},
    {"uid":"789","displayName":"User 789","mail":"789@example.com"},

The secret to extending the Autocomplete plugin is the ability to overwrite certain core functions, primarily parse. The internal version of this function simply loops over each line of the returned data and “parses” it into an array of objects, each containing the following attributes:

  • data – the entire entry
  • value – the default display value
  • result – the data to populate the input element on selection

You can overwrite this by passing your own parse function as part of the options object to autocomplete. Mine also includes a custom formatItem function for displaying each entry.

var acOptions = {
    minChars: 3,
    max: 100,
    dataType: 'json', // this parameter is currently unused
    extraParams: {
        format: 'json' // pass the required context to the Zend Controller
    parse: function(data) {
        var parsed = [];
        data = data.users;
        for (var i = 0; i < data.length; i++) {
            parsed[parsed.length] = {
                data: data[i],
                value: data[i].displayName,
                result: data[i].displayName
        return parsed;
    formatItem: function(item) {
        return item.displayName + ' (' + item.mail + ')';

The autocomplete plugin will now accept and parse JSON data.

Another thing I wanted to do with this page was to show one value but use another. In this case, I only want to display the user names and email addresses and use the UID without displaying it or putting it into the form field. This is where having each item available as a JSON object comes in very handy.

For this trick, I’ll add a hidden input field and place the UID into that when an item is selected. Here’s my form field

<input type="text" id="user_id" name="user_id">

and here’s the JavaScript

// autocomplete options as above
jQuery(document).ready(function($) {
        .autocomplete('/path/to/ajax/data/source', acOptions)
        .attr('name', 'display_name')
        .after('<input type="hidden" name="user_id" id="ac_result">')
        .result(function(e, data) {

The reason I changed the name attribute of the original input and gave it to the new hidden one is so I can still submit the form normally and work with the submitted “user_id” value.

The Autocomplete result function receives the selected item’s data property when an item is selected. With the above configuration, this is the actual JSON object