title: Firefox Throws error with this js code(ReferenceError: event is not defined) need fix
body: <p>In chrome: if i excute this code(javascript)  </p>
  
  <pre><code> function abc(event){
        console.log('hello: '+event);
      }
  abc(event);
  </code></pre>
  
  <p>the above code gives output as :
  "hello:undefined"</p>
  
  <p>but same code if we excute in firefox we get error
  what is the simple solution for this.</p>