Simple OOP concept in javascript

simple-oop.js

//how i started understanding my javascript oop concept based on ES5
//welcome comment and and 
var Bank = function(name,acct_bal){
    this.name = name;    this.acct_bal = acct_bal;
}

Bank.prototype.deposit = function(amount){  
  this.acct_bal += amount;    
  console.log("Deposited =$" + amount + "\nYour balance is $" + this.acct_bal);
  
}
Bank.prototype.withdraw = function(amount){  
  this.acct_bal -= amount;    
  console.log("Debited =; $" + amount + "\nYour balance is $" + this.acct_bal);
  
}

function main(){
    euroBank = new Bank("Peter", 2000);    
    var choice;    
    choice = parseInt(window.prompt("Enter 1 to Deposit\nEnter 2 to Withdraw"));
    while(choice !== 0){        
      amount = parseInt(window.prompt("Enter Amount"));  
    if(choice === 1){     
      euroBank.deposit(amount); 
    }else if(choice == 2){  
        if(amount > this.acct_bal){ 
          console.log("You cant withdraw more than the available balance");
          console.log("Available Balance is " + this.acct_bal);            
          
        }else{               
          euroBank.withdraw(amount);            
        }
        }else{            
          console.log("Wrong Choice Input");
        }        
            choice = parseInt(window.prompt("Enter 1 to Deposit\nEnter 2 to Withdraw")); 
        }
  
}
main();