arrayComparisonPrototype.js

myArray = [1,2,3,4,5];
mySecondArray = [1,2,3,4,5];
myThirdArray = [1,2,3,9,5];

Array.prototype.isEqualTo = function ( compareTo ) {
  if ( this.length !== compareTo.length ) return false;
  for ( var i = 0; i < this.length; i ++ ){
    if ( this[i] !== compareTo[i] ) return false;
  }
  return true;
}

console.log(myArray.isEqualTo(mySecondArray));
// true
console.log(myArray.isEqualTo(myThirdArray));
// false