var MAX_PROFILER_TIME   = 3;

function Profiler( profiler_threshold )
{

   this.Start           = Profiler__Start;
   this.Stop            = Profiler__Stop;
   this.ReportProblem   = Profiler__ReportProblem;
   this.Threshold       = profiler_threshold &&
                            typeof( profiler_threshold ) != 'undefined' &&
                            !isNaN( profiler_threshold ) ?
                              parseInt( profiler_threshold, 10 ) :
                              MAX_PROFILER_TIME;
   this.LastDiff        = 0;

   this.Start( );
}

function Profiler__Start( )
{
   if ((document.all && navigator.appVersion.toLowerCase().indexOf ('mac') == -1) || document.getElementById) {
      this.__Timer   = new Date( );
   }
}

function Profiler__Stop( )
{
   if ((document.all && navigator.appVersion.toLowerCase().indexOf ('mac') == -1) || document.getElementById) {
      var start_date    = this.__Timer;
      var stop_date     = new Date( );
      var start_ms      = start_date.getTime( );
      var stop_ms       = stop_date.getTime( );
      var diff          = stop_ms - start_ms;

      this.LastDiff     = diff;
   }
}

function Profiler__ReportProblem( )
{
   if ( this.LastDiff > this.Threshold * 1000 ) {
      var info = new Object( );
      info.URL       = document.location + "";
      info.RawTime   = this.LastDiff; // ms
      info.HRTime    = this.LastDiff + "ms (" + parseInt( this.LastDiff / 1000, 10 ) + " sec)"; // Human readable time
      info.Message   = "User experienced slow load. URL [" + info.URL + "], Time: " + info.HRTime;
      return info;
   }
   return null;
}