function addEngine()
{
    if ((typeof window.sidebar == "object") && (typeof window.sidebar.addSearchEngine == "function")) { 
        window.sidebar.addSearchEngine("http://www.fivesign.com/assets/plugins/fivesign.xml",
            "http://www.fivesign.com/favicon.ico", "General", 0
        );
    } else {
        alert("Sorry, you need a Mozilla-based browser to install a search plugin.");
    } 
}