Can you restrict entering invalid keystrokes with jQuery UI autocomplete combobox?

Question

When using the jQuery UI autocomplete combobox, I would thought there would be an option to force only a valid key entry based on the list. Is there any way to not allow invalid keys, so you can only enter valid items in the list? Also, is there a way to set a default value of the combobox?

If my list has (C#, Java, Python)

I can start typing "abcds . ." and it lets me type it in. I want only valid entries to be allowed.

Answer 1

UPDATED 2

Tested on
Internet Explorer 6 and later
Chrome
Firefox
Opera

Demo: http://so.lucafilosofi.com/can-you-restrict-entering-invalid-keystrokes-with-jquery-ui-autocomplete-combobox

Core JavaScript code:

    var Tags = ['csharp', 'java', 'python' ];

    $("#autocomplete").keypress(function(event) {
        //Firefox workaround..
        if (!event.which &&
            ((event.charCode || event.charCode === 0) ? event.charCode: event.keyCode)) {

            event.which = event.charCode || event.keyCode;
        }
        var charCode = String.fromCharCode(event.which).toLowerCase();
        var search_val = this.value + charCode;
        var x = search_val.length - 1;
        var match;
        for (var i = 0; i < Tags.length; i++) {
            if (charCode == Tags[i][x] && Tags[i].indexOf(search_val) != -1) {
                match = true;
            }
        }
        //Backspace functionality added!
        if (!match && event.which != 8 ) {
            event.preventDefault();
        }
    });

NOTE:

1. force only valid key entry based on the list;
2. set a default value;
3. lightweight implementation ;-)

Let me know!

Answer 2

After setting up your autocomplete, use this code to prevent the space character and equals character (ASCII code 32 and 61). And to set a default;

     $("#myautocompletectrl").keypress(function (e) {
        if (e.which == 32 | e.which == 61) {
          e.preventDefault();
        }
     }).val('mydefaultvalue');

It acts like the key was never pressed (as you say you wanted).

Tested on Firefox 3.63 and jQuery UI 1.8 Autocomplete.

Also, if you find that you additionally want to implement the mustMatch functionality in the jQuery UI 1.8 autocomplete, then look here: How to implement "mustMatch" and "selectFirst" in jQuery UI Autocomplete?

EDIT: I see you've already read and commented on my post.... :)

Answer 3

Your question also appears to be a common request on the jQuery plugin forum and in How to implement “mustMatch” and “selectFirst” in jQuery UI Autocomplete people have been discussing this issue.

The accepted answer for this question works. So Doc Hoffiday's solution really deserves the reputation points.

Alternatively you could use Jörn Zaefferer's autocomplete with the "mustMatch" option.

<script type="text/javascript">
$(document).ready(function(){
    var availableTags = ["csharp", "java", "python"];
    $("#tags").autocomplete(availableTags, {
        mustMatch: true
    });
});
</script>

<input id="tags" />

UPDATE

Initially, I had missed that you wanted a combobox solution. Thanks for making that clearer.

I have tweaked the combobox example.

I needed to make a few changes to make it actually work within a form. I introduced a short delay to ensure that the events happened in the right order. Other than that I inserted Doc Hoffiday's solution.

I used a "change" event, but you might also be able to get something working using the "close" event. I hate to say it, but my experience so far of working with the new jQuery UI autocomplete is that it is a bit unreliable. Things seem to mess up when you have more than one type of event callback configured.

UPDATE 2

I added a new custom selector based on Doc Hoffiday's solution so that the entered text is not overwritten when it matches the beginning of valid option. I have also updated it so that the source to restrict the options offered to more exact matches. I hope this is closer to your requirements.

I have tweaked my previous combobox example.

Answer 4

$("#myautocompletectrl").keypress(function (e) {
    if (e.which == 32 | e.which == 61) {
      e.preventDefault();
    }
 }).val('mydefaultvalue');

it works for me... thank youuu :D