//设为首页   
function setHomepage(){   
    if (document.all){   
    document.body.style.behavior='url(#default#homepage)';   
    document.body.setHomePage(document.URL);   
  }else if (window.sidebar){   
        if(window.netscape){   
       try{    
          netscape.security.PrivilegeManager.enablePrivilege("UniversalXPConnect");    
       }catch (e){    
                    alert( "该操作被浏览器拒绝，如果想启用该功能，请在地址栏内输入 about:config,然后将项 signed.applets.codebase_principal_support 值该为true" );    
       }   
        }    
    var prefs = Components.classes['@mozilla.org/preferences-service;1'].getService(Components. interfaces.nsIPrefBranch);   
    prefs.setCharPref('browser.startup.homepage',document.URL);   
    }   
}