+1  A: 

FF does not allow you to access DOM elements as javascript variables named by their ID.

You need to use getElementById instead.

sje397
+1 Wow, i wasn't aware that any browser did... but i suppose i tried not to write JS in the bad old days of IE<=6 where much of this madness no doubt originated
tobyodavies
A: 

in the last script block, playerFive is never defined anywhere, you probably want

document.getElementById('playerFive').onclick=handler;
tobyodavies
A: 

You can try this code

 if(document.all)// For IE
 {   
       document.getElementById('playerFive').attachEvent('onclick',handler);
 }
 else // For FF
 {
       document.getElementById('playerFive').addEventListener('click',handler,false);
 }
ismailperim
A: 
<html>
 <head>
  <script type="text/javascript">
    window.onload = function() { 
        var div = document.getElementById("dvClickMe");
        if(div.attachEvent)
            div.attachEvent('onclick', sayHello); 
        else
            div.setAttribute('onclick', 'sayHello()');
    }
    function sayHello() { alert("Hello!"); }
  </script>
 </head>
 <body>
   <div id="dvClickMe">Click me!</div>
 </body>
</html>

The above code is working on IE8 and FF 3.6.10

Ramiz Uddin