What does the command: var a, foo = "foo"; mean? (Jasmin toBeTruthy)

i'm currently learning Jasmine. One of the examples in the intro (http://ift.tt/1vhJfTg), for Included Matchers,

show the following code:

it("The 'toBeTruthy' matcher is for boolean casting testing", function() {
    var a, foo = "foo"; 

    expect(foo).toBeTruthy();
    expect(a).not.toBeTruthy();
  });

What does

     var a, foo = "foo";   

mean?

Is it two definition of variables, a and foo and initializing them as a "foo" string?

a = false and foo = true? Because maybe they were predefined as:

var a = null;
var foo = "foo";

thanks