Just tried to understand the last bit myself. So he's doing 0["constructor"] which gives the constructor of a number, Number. Then he's 0["constructor"]["const

Just tried to understand the last bit myself. So he's doing 0["constructor"] which gives the constructor of a number, Number. Then he's 0["constructor"]["constructor"] gives the constructor of Number, which is like a function, so he gets Function. var y = (0)["constructor"]["constructor"]; y == Function; // true Then he basically does this ($.$ == Function): Function( Function( "return \"alert('I love you');\"" )() )(); The inner function just returns the string "alert('I love you');", which then becomes the body for the outer function. I don't know why they didn't make it: Function ("alert('I love you');")(); Maybe they needed more chars for the heart. That was a good little crash course in javascript Function constructors!