What does ':' (colon) do in JavaScript?

I'm learning JavaScript and while browsing through the jQuery library I see : (colon) being used a lot. What is this used for in JavaScript?

// Return an array of filtered elements (r)
// and the modified expression string (t)
   return { r: r, t: t };

Solution 1:

var o = {
    r: 'some value',
    t: 'some other value'
};

is functionally equivalent to

var o = new Object();
o.r = 'some value';
o.t = 'some other value';

Solution 2:

And also, a colon can be used to label a statement. for example

var i = 100, j = 100;
outerloop:
while(i>0) {
  while(j>0) {
   j++

   if(j>50) {
     break outerloop;
   }
  }
i++

}