Sometime you see that we need event object in javascript.
Here is some code how can we pass event.
 function test(e){
  console.log(e); 
  e.preventDefault();
  console.log("you are not going to redirect");
 }
HTML
 <a href="www.google.com" onclick="test(event)">GOOGLE</a>
Just pass the event in function argument if you want to pass event in function.