Hmmm.... i got this to work just fine... perhaps differences in "ui.js" (as you can see, mine is right off the official site) ?
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http:// www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <title>Autocomplete and jQuery UI Test</title> <script src="http://ui.jquery.com/js/jquery.js" type="text/ javascript"></script> <script src="http://jquery.bassistance.de/autocomplete/lib/ jquery.bgiframe.min.js" type="text/javascript"></script> <link href="http://jquery.bassistance.de/autocomplete/ jquery.autocomplete.css" rel="stylesheet" type="text/css" /> <script src="http://jquery.bassistance.de/autocomplete/ jquery.autocomplete.js" type="text/javascript"></script> <script src="http://ui.jquery.com/js/ui.js" type="text/ javascript"></script> <script type="text/javascript"> $(document).ready(function() { var data = "Steve Roger Adam John".split(" "); $("#autofield").autocomplete(data); }) </script> </head> <body> <form> <input type="text" id="autofield" name="autofield" /> </form> </body> </html>