I've been studying about JS objects and I faced the description of methods. It says that a method is "a shorthand for a function assigned to the method's name". In other words, a method is a function, right? But the thing is, where do the methods like parseInt() and toLocaleString() come from if I haven't created a function to turn a float-point number into a integer? I googled about built-in functions, but I haven't found any documentation answering this question.
They are built into the js engine, i.e. it does provide the implementation and creates the function (method) in the environment before running any JS code.