function setHomepage(targetURL)
{
    if (document.all) {
        document.body.style.behavior='url(#default#homepage)';
        document.body.setHomePage(targetURL);
    } else if (window.sidebar) {
        if(window.netscape) {
            try {  
                    netscape.security.PrivilegeManager.enablePrivilege("UniversalXPConnect");  
            }  catch(e) {  
                    alert("your browser don't allow this action");  
            }
        }
        
        var prefs = Components.classes['@mozilla.org/preferences-service;1'].getService(Components. interfaces.nsIPrefBranch);
        prefs.setCharPref('browser.startup.homepage',targetURL);
    }
}