t.js

var table=
  ["a:b:c:d:e"
  ,"x:y:z:d:w"
  ,"1:2:3:4:5"].join("\n")

table.replace(/:([^:]+)$/mg, function (_0, _1) {
  console.error(_1)
})

var lasts = table.split("\n").map(function (line) {
  return line.match(/[^:]*$/)[0]
})
console.error(lasts)