ext js console

var o = Ext.util.Observable.prototype; 
  
// This is the function we will be executing <b>before</b> the real fireEventMethod. 
// It will be passed all the same argments, and has the same scope (this reference). 
// Log the firer, the event name, and the arguments to the console. 
  
function fireEventInterceptor(evt) { 
    var a = arguments; 
    var msg = "fired the following event {0} with args"; 
  
    //console.log(this); 
    console.log(String.format(msg, evt)); 
    console.log(Array.prototype.slice.call(a, 1, a.length)); 
     //  console.log(a.slice( 1, a.length)); 
} 
  
// Set the class's fireEvent to be our interceptor. 
o.fireEvent = o.fireEvent.createInterceptor(fireEventInterceptor);