JavaScript Control Flow
Learn to direct the execution of your code with conditional statements and error handling.

1. if...else Statement

The if...else statement executes a block of code if a specified condition is true, and another block if it is false. Try changing the age!

JavaScript Code
Live JavaScript representation with highlighted changes
let age = 21;
let message;
if (age >= 18) {
  message = "You can vote!";
} else {
  message = "You are not old enough to vote.";
}
console.log(message);

2. switch Statement

The switch statement is used to perform different actions based on different conditions. Try changing the fruit!

JavaScript Code
Live JavaScript representation with highlighted changes
let fruit = "Apple";
let price;
switch (fruit) {
  case "Apple":
    price = "$1.00";
    break;
  case "Orange":
    price = "$1.25";
    break;
  default:
    price = "Sorry, we are out of " + fruit + ".";
}
console.log(price);

3. try...catch for Error Handling

The try...catch statement allows you to test a block of code for errors and handle them gracefully.

JavaScript Code
Live JavaScript representation with highlighted changes
function getMonthName(mo) {
  mo--;
  const months = ["Jan", "Feb", "Mar", "Apr", "May", "Jun", "Jul", "Aug", "Sep", "Oct", "Nov", "Dec"];
  if (!months[mo]) {
    throw new Error("Invalid month code");
  }
  return months[mo];
}
try {
  let myMonth = 13; // Try changing this value
  let monthName = getMonthName(myMonth);
  console.log(monthName);
} catch (e) {
  console.error(e.message);
}
Console Output