Does a jQuery plug-in exist for replacing select/combo box?
I tried SexyCombo, and it is as close to what I want, but it doesn't complete if you are writing from middle, only from beginning.
I have 2 levels of categories (20 top level categories, and with subcategories in total 120 categories), so when user is submitting an entry, he must find desired category as soon as possible.
So... 2 levels + autocomplete populate text even if you write middle letters.
Or any other solution?
jQuery 1.8.1 has an example of this under autocomplete. It's very easy to implement.
Have a look at the following example of the jQueryUI Autocomplete, as it is keeping a select around and I think that is what you are looking for. Hope this helps.
I know this has been said earlier, but jQuery Autocomplete will do exactly what you need. You should check out the docs as the autocomplete is very customizable. If you are familiar with javascript then you should be able to work this out. If not I can give you a few pointers, as I have done this once before, but beware I am not well versed in javascript myself either, so bare with me on this.
I think the first thing you should do is just get a simple autocomplete text field working on your page, and then you can customize it from there.
The autocomplete widget accepts JSON data as it's 'source:' option. So you should set-up your app to produce the 20 top level categories, and subcategories in JSON format.
The next thing to know is that when the user types into your textfield, the autocomplete widget will send the typed values in a parameter called "term".
So let's say you first set-up your site to deliver the JSON data from a URL like this:
/categories.json
Then your autocomplete source: option would be 'source: /categories.json'.
When a user types into the textfield, such as 'first-cata...' the autocomplete widget will start sending the value in the 'term' parameter like this:
/categories.json?term=first-cata
This will return JSON data back to the widget filtered by anything that matches 'first-cata', and this is displayed as an autocomplete suggestion.
I am not sure what you are programming in, but you can specify how the 'term' parameter finds a match. So you can customize this, so that the term finds a match in the middle of a word if you want. Example, if the user types 'or' you code could make a match on 'sp*or*ts'.
Lastly, you made a comment that you want to be able to select a category name but havethe autocomplete widget submit the category ID not the name.
This can easily be done with a hidden field. This is what is shown in the jQuery autocomplete docs.
When a user selects a category, your javascript, should update a hidden field with the ID.
I know this answer is not very detailed, but that is mainly because I am not sure what you are programming in, but the above should point you in the right direction. The thing to know is that you can do practically any customizing you want with this widget, if you are willing to spend the time to learn it.
These are the broad strokes, but you can look here for some notes I made when I implemented something similar to what you want in a Rails app.
Hope this helped.