The release of the Autocomplete widget in jQuery UI 1.8 was a pretty important milestone for the jQuery UI team. If you’ve looked at the widget, you may have noticed that there are only four options, far fewer than our other plugins. Unlike progressbar, our plugin with the fewest options, Autocomplete’s small API isn’t a direct result of the plugin’s simplicity. In fact, Autocomplete is quite complex.
When designing the Autocomplete widget, we started with Jörn Zaefferer’s Autocomplete plugin, which has 21 options, as a model. Admittedly, Jörn’s plugin does more for you out of the box than ours, but our smaller API is just as flexible and has the bonus of being easier to learn and use. A lot of thought, discussion, and prototyping went into narrowing down the list of 21 options to 4.
Out of the box, Autocomplete provides support for local data sources and remote (JSON) data sources by simply providing an array or url to the source option. Support for JSONP, XML, and caching can all be layered on top in just a few lines of code.
There’s also a set of extensions hosted by me that provide additional options for the Autocomplete widget. The html option (demo) allows you to specify whether your labels should be interpreted as HTML or text. There’s also the selectFirst option (demo) which automatically activates the first item when the menu is shown, reducing the number of keystrokes necessary to select an option. The autoSelect option (demo) allows a user to type out a valid option and tab away from the field without having to select the item from the menu. If the value entered by the user is valid, the select event will be triggered just as if the user had explicitly chosen the item from the menu. I also have an accent folding extension (demo) that makes it easier for users to select values with accented characters. For example, if there is an item with the text “Jörn”, the user would normally have to type the umlaut in order to see the item. However, if the accent folding extension is loaded, the user can type “Jorn” and they will still see the result.
Going a step further, you can use custom data formats and define custom displays. For example, you can categorize the results or display additional information such as item descriptions and images. There’s even an example of expandable search results (Note: this is just a prototype based on a demo from Roman Chyla, it is not full-featured. See the forum thread for more details). You can even support multiple words from a single text field.
Finally, there’s the combobox demo that brings Autocomplete functionality to select elements. The combobox hides the select element and instead displays a text field for the user to type in. The possible values are determined by parsing the options from the select, and the user can view all options by clicking a button next to the text field. For a detailed explanation of how the combobox works, check out Jörn’s article on Learning jQuery.
