function close_win(){

  var nvua = navigator.userAgent;

    if(nvua.indexOf('MSIE') >= 0){

      if(nvua.indexOf('MSIE 5.0') == -1) {

        top.opener = '';

      }

    }

    else if(nvua.indexOf('Gecko') >= 0){

      top.name = 'CLOSE_WINDOW';

      wid = window.open('','CLOSE_WINDOW');

    }

  top.close();

}