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

function st_extract_last(term) {
    return st_split(term).pop();
}

function st_init_autocomplete(p_target, p_url, p_min_chars) {
    // Dynamic width ?
    p_width = jQuery("" + p_target).width();
    if (p_width === 0) {
        p_width = 200;
    }

    // Init jQuery UI autocomplete
    jQuery(p_target).bind("keydown", function(event) {
        // don't navigate away from the field on tab when selecting an item
        if (event.keyCode === jQuery.ui.keyCode.TAB &&
            jQuery(this).data("ui-autocomplete").menu.active) {
            event.preventDefault();
        }
    }).autocomplete({
        minLength: p_min_chars,
        source: function(request, response) {
            jQuery.getJSON(p_url, {
                term: st_extract_last(request.term)
            }, response);
        },
        focus: function() {
            // prevent value inserted on focus
            return false;
        },
        select: function(event, ui) {
            var terms = st_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;
        }
    });
}