id doesn't refer to an attribute, it is a integer that tells the program where in the array to store tabLink.
Code:
id=0;
tabLink[id]="test"//these two lines have the same effect as tabLink[0]="test"
id=1
tabLink[id]="foo"//these two lines are the same as tabLink[1]="foo"
after running these four lines tablink now is
["test", "foo"]
the id value tells it were to store "tabLink" in the array