text: var _request = new RequestHandler();
  "use strict";
  
  /* object handeling "Overview" status updates every few seconds */
  function PingObj( ){
  
  
    /* query get_status.php */
    this.read = read;
    function read( ){
        var url = '/tools/ping_worker.php';
        var pdata = 'cmd=read'; //post data as string
        var callback;
  
  
        /* this will be executed after a successful http request */
        callback = function(ret){
          var ele = document.getElementById('ping_out');
          if( ele.innerHTML !== ret ){
            ele.innerHTML = '';
            ele.innerHTML = ret;
  
            if( ret.search('PINGDONE') !== -1 ){
              clearInterval(timr2);
              document.getElementById("btn_ping").disabled = false;
              console.log("ended timr2");
            }
          }
        };
  
        _request.post( 'ping_read', url, pdata, callback);
    }
  
  
    /* query get_status.php */
    this.ping = ping;
    function ping( host_ele ){
        var url = '/tools/ping_worker.php';
        var host = document.getElementById(host_ele).value;
        var se = document.getElementById('ping_if');
        var intif = se.options[se.selectedIndex].value;
        var pdata = 'cmd=ping&IP=' + host + '&IF=' + intif; //post data as string
        var callback;
  
  
        /* this will be executed after a successful http request */
        callback = function(ret){
          var ele = document.getElementById('ping_out');
          if( ele.innerHTML !== ret ){
            ele.innerHTML = '';
            ele.innerHTML = ret;
          }
        };
  
        _request.post( 'ping_write', url, pdata, callback);
    }
  
    }