<input type="text" id="selector">
var availableTags = [
"ActionScript",
"AppleScript",
"Asp",
"BASIC",
"C",
"C++",
"Clojure",
"COBOL",
"ColdFusion",
"Cycle",
"Erlang",
"Fortran",
"Groovy",
"Haskell",
"Java",
"JavaScript",
"Lisp",
"Perl",
"PHP",
"Python",
"Ruby",
"Scala",
"Scheme"];
$("#selector").autocomplete({
source: availableTags,
change: autoCompleteChanged
});
function autoCompleteChanged(event, ui) {
alert($('#selector').val());
}