JavaScript illustrates that methods are the same as functions with an implicit parameter "this"

methodAsFunction

var completeSale = function(num) {
    console.log("Sale " + num + ": selling " + this.items + " to " + this.customer);
   }

var foo = {
   customer: "Fred",
   items: ["carrot","eggs"],
   complete: completeSale
};

console.log("method style:")
foo.complete(99);

console.log("function style:")
completeSale.call(foo, 100)