Open the JS console and try

"abc".include("a")

Happens this

"abc".include is not a function

Add include method on String running this

String.prototype.include = function(content) {
  return this.indexOf(content) != -1;
}

Try again

"abc".include("a")

And see this return

true

Try another char

"abc".include("x")

And see this return

false

🗓 2016-04-08
1085 👀