Control flow with if and switch

Using if/else and switch statements, we can control how code is execution.

if statement

The if statement is closely similar to any other programming language. Remember to NOT close any if expression statements with a semicolon.

if (score > 10) {
  alert("Congratulatiosn! You got 100%!");
} else if (score > 8) {
  alert("Wow! You rocked that quiz!");
} else if (score > 7) {
  alert ("You passed");
} else {
  alert ("Please review your notes and try again.");
}

The alert() is a browser object model function takes in a string and outputs it as a pop-up dialog message to the user.

Ternary if statement

You may have a ternary if statement for cleaner code.

Take a look at the code below. The left-most statement is the conditional. If it evaluates to true, the middle statement is executed. If false, the right-most statement is executed.

(name == "John") ? "Hello John" : "Hello unknown person";

switch statement

If you have several else-if statements, you may want to consider using a switch statement.

The switch statement evaluates an expression or a given variable, then delegates the task to whichever case it matches. If no matches are found, then the default is run.

switch (language) {
  case 'en':
    greeting = 'Hello world';
    break;
  case 'fr':
    greeting = 'Bonjour le monde';
    break;
  case 'es':
    greeting = 'Hola mundo';
  default:
    greeting = 'Greetings, earthlings';
    break;
}

Make sure to place a break; command after every case - otherwise JavaScript will continue to execute the next case (which is something you'll most often not want).

Aching back from coding all day?

Foam Seat Cushion

Aching back from coding all day? Try Back Problems

This foam seat cushion relieves lowerback pain, numbness and pressure sores by promoting healthy weight distribution, posture and spine alignment. Furthermore, it reduces pressure on the tailbone and hip bones while sitting. Perfect for sitting on the computer desk for long periods of time.

$ Check price
99.9599.95Amazon 4.5 logo(9,445+ reviews)

More Back Problems resources

Build modern and responsive webpages

Responsive Typography

Build modern and responsive webpages Try Front-end

Responsive web design helps your site maintain its design integrity on a variety of screen sizes, but how does it affect your typography? With this practical book, graphic designers, web designers, and front-end developers alike will learn the nuts and bolts of how to get the best appearance from type without sacrificing performance on any device.

$ Check price
24.9924.99Amazon 4.5 logo(3+ reviews)

More Front-end resources

Ad