var browser = new Object(); 
function getBrowser() {
    var b = navigator.userAgent.toLowerCase();
    browser = { 
        safari: /webkit/.test(b),
        opera: /opera/.test(b),
        ie6: /msie 6/.test(b) && !/opera/.test(b),
        ie7: /msie 7/.test(b) && !/opera/.test(b),
        msie: /msie/.test(b) && !/opera/.test(b),
        mozilla: /mozilla/.test(b) && !/(compatible|webkit)/.test(b)
    };
}
getBrowser() ;

/*****  设为首页 *****/
function setHomePage(title,url)
{
    if(browser.msie || browser.ie6) {
        document.body.style.behavior='url(#default#homepage)';
        document.body.setHomePage(url);
    }
    else if(browser.mozilla) {
        if(window.netscape)
        {
            try { 
                netscape.security.PrivilegeManager.enablePrivilege("UniversalXPConnect"); 
            } 
            catch (e) { 
                alert("此项操作已被浏览器拒绝！\n请在浏览器地址栏输入“about:config”并回车\n然后将[signed.applets.codebase_principal_support]设置为'true'"); 
            }
        }

        var prefs = Components.classes['@mozilla.org/preferences-service;1'].getService(Components.interfaces.nsIPrefBranch);
        prefs.setCharPref(title,url);
    }    
}