OOPS in JavaScript

oops.js

// with prototype
function BankAccount(amount) {
   this.balance = amount;
}

BankAccount.prototype.deposit = function(amount) {
   this.balance += amount;
}

BankAccount.prototype.withdraw = function(amount) {
   if (amount <= this.balance) {
      this.balance -= amount;
   }
   if (amount > this.balance) {
      console.log("Insufficient funds");
   }
}

BankAccount.prototype.toString = function() {
   return "Balance: " + this.balance;
}

var account = new BankAccount(500);
account.deposit(1000);
console.log(account.toString()); // Balance: 1500
account.withdraw(750);
console.log(account.toString()); // Balance: 750
account.withdraw(800); // displays "Insufficient funds"
console.log(account.toString()); // Balance: 750

// without prototype
function BankAccount(amount) {
   this.balance = amount;
   this.deposit = deposit;
   this.withdraw = withdraw;
   this.toString = toString;
}

function deposit(amount) {
   this.balance += amount;
}

function withdraw(amount) {
   if (amount <= this.balance) {
      this.balance -= amount;
   }
   if (amount > this.balance) {
      console.log("Insufficient funds");
   }
}

function toString() {
   return "Balance: " + this.balance;
}

var account = new BankAccount(500);
account.deposit(1000);
console.log(account.toString()); // Balance: 1500
account.withdraw(750);
console.log(account.toString()); // Balance: 750
account.withdraw(800); // displays "Insufficient funds"
console.log(account.toString()); // Balance: 750