assigning a function to variable is not working in javascript firefox extension -

This is not working when I try this method in the Firefox Consensus

  Var x = function (y) {returns y * y; };  

The MDN page in Firefox

But this function works very neatly in Chrome extensions and this is my knowledge in the Javascript function. Thanks in advance

There is a test extension

I think you really want Instead of outputing the console's function definition, execute the function and pass the parameter to your test code. Change:

  console.log ("x:", x);  

to:

  console.log ("x:", x (2));