JavaScript Course Interaction With User

Javascript allows us the privilege to which we can interact with the user and respond accordingly. It includes several user-interface functions which help in the interaction. Let's take a look at them one by one.

JavaScript Window alert() Method : It simply creates an alert box that may or may not have specified content inside it, but it always comes with the 'OK' button. It simply shows a message and pauses the execution of the script until you press the 'OK' button. The mini-window that pops up is called the 'modal window'.

alert('text');

Example:

alert('HI there'); // with specified content
alert(); // without any specified content

Output: It can be used for debugging or simply for popping something to the user.

JavaScript Window prompt() Method: Prompt is another user-interface function that normally contains two arguments.

prompt('text', default value);

The text is basically what you want to show the user and the default value argument is optional though it acts like a placeholder inside a text field. It is the most used interface as with it you can ask the user to input something and then use that input to build something.

Example: With default parameter.

// prompt example
let age = prompt('How old are you?', 50);

alert(`You are ${age} years old!`); 

Output:

You can enter anything and it will print that, it doesn't necessarily have to be a number. Without the default value, you have to enter something in the text field otherwise it will print a blank space simply.

Example:

// prompt example
let age = prompt('How old are you?');

alert(`You are ${age} years old!`); 

Output:

JavaScript Window confirm() Method: The confirm function basically outputs a modal window with a question and two buttons 'OK' and 'CANCEL'.

confirm('question');

Example:

// confirm example 
let isHappy  = confirm('Are you Happy?');
alert(`You are ${isHappy}`);

Output:

It will print true or false based on your choice of clicking the 'OK' button or 'CANCEL' button respectively.