Mozilla Firebug console.log() displays the answer as undefined

Question

I am using Firebug for the first time and when I type

var a = 10;
console.log("value of a: " + a);

the response I get on the console is "undefined".

I suppose the syntax was correct, and I tried using it with alert and document . It worked fine, but Firebug isn't showing any output. How can I fix this?

Note: I am talking about Firebug, the extension for Mozilla Firefox, not Firefox's built-in developer tools.

Answer 1

Separate expressions. Based on the screenshot, firefox displays the result of the first expression