function addTag(tag) {
    // Trim tag
    tag = tag.replace(/^\s+/, '').replace(/\s+$/, '');

    if (document.getElementById("adv-tags-input")) { // Tags input from Simple Tags

        var tag_entry = document.getElementById("adv-tags-input");
        if (tag_entry.value.length > 0 && !tag_entry.value.match(/,\s*$/)) {
            tag_entry.value += ", ";
        }

        var re = new RegExp(tag + ",");
        if (!tag_entry.value.match(re)) {
            tag_entry.value += tag + ", ";
        }

    } else { // Default tags input from WordPress

        tag.replace(/\s+,+\s*/g, ',').replace(/,+/g, ',').replace(/,+\s+,+/g, ',').replace(/,+\s*$/g, '').replace(/^\s*,+/g, '');
        if (jQuery('#new-tag-post_tag').val() === "") {
            jQuery('#new-tag-post_tag').val(tag);
        } else {
            jQuery('#new-tag-post_tag').val(jQuery('#new-tag-post_tag').val() + ", " + tag);
        }
        jQuery('.tagadd').click();

    }
}