Q950 Is it possible to change the value of preferences in Netscape Communicator?

<script language="JavaScript1.2"><!--
if (document.layers) {
    // request privilege
    netscape.security.PrivilegeManager.enablePrivilege('UniversalBrowserWrite');

    // set preference
    navigator.preference('browser.startup.homepage','http://www.irt.org/index.htm');

    // save preference
    navigator.savePreferences();
}
//--></script>