gistfile1.html

<input class="" type="text" value="Search" id="search">

gistfile2.js

<script src="http://code.jquery.com/jquery-latest.min.js" type="text/javascript"></script>
<script>
(function() {
    
    $("#search").autocomplete({});

    // Overrides the default autocomplete filter function to search only from the beginning of the string
    $.ui.autocomplete.filter = function (array, term) {
        var matcher = new RegExp("\\b" + $.ui.autocomplete.escapeRegex(term), "i");
        return $.grep(array, function (value) {
            return matcher.test(value.label || value.value || value);
        });
    };
})();
</script>