function __api(_method,_params,_callback,_dwo){
      _dwo = _dwo || false;   // don't wait on, for some system cron calls
      var xmlhttp = new XMLHttpRequestObj();
      if (xmlhttp == null){ alert ("Browser does not support HTTP Request"); return; }   
      xmlhttp.sc = __request_stateChanged;
      xmlhttp.cb = _callback;
      if(!_dwo){
         if(typeof __data != "undefined"){
            if(typeof __data.w != "undefined"){
               xmlhttp.w = __data.w.waitFor(_method);
            }
         }
      }
      var _url = "http://gemlit.com/e/api.php?a="+_method+"&"+_params;  // _method is in MODULE.METHOD_NAME format 
      xmlhttp.x.onreadystatechange=function(){xmlhttp.sc()};
    	xmlhttp.x.open("GET",_url,true);
    	xmlhttp.x.send(null);
   }
   function __request(_url,_callback){
      var xmlhttp = new XMLHttpRequestObj();
      if (xmlhttp == null){ alert ("Browser does not support HTTP Request"); return; }   
      xmlhttp.sc = __request_stateChanged;
      xmlhttp.cb = _callback;
      xmlhttp.x.onreadystatechange=function(){xmlhttp.sc()};
    	xmlhttp.x.open("GET",_url,true);
    	xmlhttp.x.send(null);
   }
   function __request_stateChanged(){
      if (this.x.readyState==4){
         this.x.onreadystatechange = __nofunc;
         if(typeof this.w != "undefined"){ __data.w.endOf(this.w) }
         if((this.x.responseText.substring(0,5)=="error")||(this.x.responseText=="")){
            showSysMsg(this.x.responseText);
            return
         };
      this.cb(this.x.responseText);
     }
   }

   // ========================================== VIZUALISATION OF "waiting..."
   
   function WaitingViz(_timeout){
      var me = this;
      me._timeout = _timeout;
      me._w = new Array();
      me._i = 0;
      me._len = 0;
      if(typeof __cron != "undefined"){ __cron.push(function(){me.checkTimeout()}) }
   }
   WaitingViz.prototype.checkTimeout = function(){
      var me = this;
      var now_ = new Date().getTime();
      for(var i in me._w){
         if(now_ > (me._w[i].sent + me._timeout)){
            // request timedout
            showSysMsg('warning: request timeout.releasing #'+me._w[i].id);
            me.endOf(me._w[i].id); 
         }
      }
   }
   WaitingViz.prototype.isWaiting = function(){ if(this._len==0){return false}else{return true} }
   WaitingViz.prototype.waitFor = function(caller_){
      var me = this;
      caller_ = caller_ || '';
      var a = new Array();
      a.id = me._i;
      a.caller = caller_;
      a.sent = new Date().getTime(); 
      me._w[me._i] = a;
      me._i++;
      me._len++;
      if(me._len == 1){ me.onBeginWaiting() }
      return (me._i-1);
   }
   WaitingViz.prototype.endOf = function(id){
      var me = this;
      if(typeof id == "undefined"){ return }
      if(typeof me._w[id] == "undefined"){ return }
      delete me._w[id];
      me._len--;
      if(me._len == 0){ me.onBeginIdle() }
   }
   WaitingViz.prototype.onBeginWaiting = function(){
      $("blocker").style.height = document.body.scrollHeight + "px";      
      $("blocker").style.width = document.body.scrollWidth + "px";
      $('blocker').style.zIndex = 9999999;
      $('blocker').style.cursor = 'wait';
   }
   WaitingViz.prototype.onBeginIdle = function(){
      $('blocker').style.zIndex = -1;
      $('blocker').style.cursor = '';
   }