jQuery UI Autocomplete For @ Mentions Logic

HTML

<link rel="stylesheet" href="http://ajax.microsoft.com/ajax/jquery.ui/1.8.7/themes/black-tie/jquery-ui.css">
<script src="http://ajax.aspnetcdn.com/ajax/jquery.ui/1.8.7/jquery-ui.min.js"></script>
<input id="tags" />

CSS

input { width:550px; }

JavaScript

var availableTags = [
    "ActionScript",
    "AppleScript",
    "Asp",
    "BASIC",
    "C",
    "C++",
    "Clojure",
    "COBOL",
    "ColdFusion",
    "Erlang",
    "Fortran",
    "Groovy",
    "Haskell",
    "Java",
    "JavaScript",
    "Lisp",
    "Perl",
    "PHP",
    "Python",
    "Ruby",
    "Scala",
    "Scheme"
    ];

function split(val) {
    return val.split(/@\s*/);
}

function extractLast(term) {
    return split(term).pop();
}

$("#tags")
// don't navigate away from the field on tab when selecting an item
.bind("keydown", function(event) {
    if (event.keyCode === $.ui.keyCode.TAB && $(this).data("autocomplete").menu.active) {
        event.preventDefault();
    }
}).autocomplete({
    minLength: 0,
    source: function(request, response) {
        var term = request.term,
            results = [];
        if (term.indexOf("@") >= 0) {
            term = extractLast(request.term);
            if (term.length > 0) {
                results = $.ui.autocomplete.filter(
                availableTags, term);
            } else {
                results = ['Start typing...'];
            }
        }
        response(results);
    },
    focus: function() {
        // prevent value inserted on focus
        return false;
    },
    select: function(event, ui) {
        var terms = split(this.value);
        // remove the current input
        terms.pop();
        // add the selected item
        terms.push(ui.item.value);
        // add placeholder to get the comma-and-space at the end
        terms.push("");
        this.value = terms.join("");
        return false;
    }
});