Execute a function on each element
array.forEach(function(element, index, array) { ... })
Add one or more items at the end: [1] => [1, 2, 3]
[1] => [1, 2, 3]
array.push(item1, item2, ...)
Remove an element from the end: [1, 2] => [1]
[1, 2] => [1]
array.pop()