Javascript function as a variable? -

here code example mozilla javascript closures:

function makefunc() {   var name = "mozilla";   function displayname() {     alert(name);   }   return displayname; }  var myfunc = makefunc(); myfunc(); 

why return inner function displayname() variable displayname, is, without parentheses?

return displayname()

1. invoke alert @ line var myfunc set ,
2. return undefined.

return displayname (without parentheses) returns function whereas former (with parentheses) invokes function , returns whatever function returns. function displayname doesn't have explicit return statement implied return type undefined.