String & Array func

string-array.js

var s = 'abcde'

// s.substr(1/*start*/, 3/*count*/) // bcd
s.substring(1/*start*/, 3/*end(not included)*/) // bc, not changed
s.slice(1/*start*/, 3/*end(not included)*/) // bc, not changed
s.slice(1,3) === s.substring(1,3)

var a = ["a", "b", "c", "d", "e"]

a.slice(1/*start*/, 3/*end(not included)*/) // ['b', 'c'], not changed
a.splice(1/*start*/, 3/*count*/) // ['b', 'c', 'd'], a become ['a', 'e']
a.splice(1/*start*/, 3/*count*/, 'x'/*inject*/) // ['b', 'c', 'd'], a become ['a', 'x', 'e']