How jQery Works--the Basics

How jQery Works--the Basics

I was following along with the How jQuery Works the Basics on the website and one of the starter examples is : 

  1.     
    
     
    
      $( document ).ready(function() {
     
    
    
    
    
    
     
    
       
     
    
    
    
    
    
     
    
       $( "a" ).click(function( event ) {
     
    
    
    
    
    
     
    
       
     
    
    
    
    
    
     
    
       alert( "Thanks for visiting!" );
     
    
    
    
    
    
     
    
       
     
    
    
    
    
    
     
    
       });
     
    
    
    
    
    
     
    
       
     
    
    
    
    
    
     
    
      });
I was playing around with the code and I removed the word event from the click function and everything still worked the same. What then is the purpose of event ?