if (navigator.userAgent.indexOf("MSIE") > 0) {
      if (navigator.userAgent.indexOf("MSIE 6.0") > 0) {
        window.opener = null;
        window.close();
      }
      else {
        window.open('', '_top');
        window.top.close();
      }
    }
    else if (navigator.userAgent.indexOf("Firefox") > 0) {
      window.location.href = 'about:blank '; //火狐默认状态非window.open的页面window.close是无效的    
      //window.history.go(-2);     
    }
    else {
      window.opener = null;
      window.open('', '_self', '');
      window.close();
    }