code: function xbDebugApplyFunction(funcname, funcref, thisref, argumentsref)
  {
      var rv;
  
      if (!funcref)
      {
          alert('xbDebugApplyFunction: funcref is null');
      }
  
      if (typeof(funcref.apply) != 'undefined')
          return funcref.apply(thisref, argumentsref);
  
      var applyexpr = 'thisref.xbDebug_orig_' + funcname + '(';
      var i;
  
      for (i = 0; i < argumentsref.length; i++)
      {
          applyexpr += 'argumentsref[' + i + '],';
      }
  
      if (argumentsref.length > 0)
      {
          applyexpr = applyexpr.substring(0, applyexpr.length - 1);
      }
  
      applyexpr += ')';
  
      return eval(applyexpr);
  }
docs: emulate functionref.apply for IE mac and IE win < 5.5