JavaScript array slice versus delete

Question

Is there any reason why one should be used over the other?

e.g.

var arData=['a','b','c'];
arData.slice(1,1);//removes 'b'

var arData=['a','b','c'];
delete arData[1];//removes 'b'

Answer 1

delete only makes that certain location of the array undefined but the array still contains 3 items: ['a',undefined,'c']

the other way to do it is splice and not slice. splice totally removes that item and it's location, so you end up with ['a','c']

Answer 2

delete leaves you with [ 'a', undefined, 'c' ]

splice leaves you with [ 'a', 'c' ]

slice doesn't do anything to the original array :) But it returns [ 'b' ] in your code