In JavaScript, collections don't have many advantages over arrays, because JavaScript is a loosely typed language. Given the similarity to arrays, why do we need collection objets? The major reason is ease of access and ease of maintenance:

• Members can be retrieved based on either their key value of their index value. The item() method retrieves a member from the collection.
  
• Members can be added before or after an existing member based on the laters index value. The add() method adds a member to the collection.
  
• Members can be deleted based on their index value. Multiple deletions, however, should be done backwards, from higher index values to lower ones, since the collection is reindexed after each deletion. The remove() method deletes a member from the collection.
  

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