You already know about the existence of
alert function that displays
the given message on the screen. There
is also a similar function
that allows you to get some text from the user.
Let's ask a user name as an example:
prompt('What is your name?');
Run the code above to see the window
displayed by the
Type in your name and click the button.
If you have done all the actions
described above, then the name you entered
will appear in our script.
In order to get access to the entered name,
the result of the
must be assigned to some variable,
for example, like this:
let name = prompt('What is your name?');
Let's display the name entered earlier
on the next line of the code using the
let name = prompt('What is your name?'); alert('Your name: ' + name);
You should understand that when calling
prompt function, further script
execution is blocked until the appropriate
data is entered. In general, the
function works the same way, except it waits
for the appropriate button to be pressed.
By the way, you don't have to use a variable:
alert('Your name: ' + prompt('What is your name?'));
Ask the user's age using the
function. Print user entered age with
Issue with types
Note that the
prompt function always
returns a string, even if the user entered a
number. For example, consider the following script:
let num1 = prompt('Enter the first number'); let num2 = prompt('Enter the second number'); alert(num1 + num2); // concatenates numbers like strings
Modify the above code so that numbers are summed not like strings.
prompt function to ask
the user for the side of a square.
Display the area of the given square.
Use the two functions
to ask the user for the sides of a
rectangle. Display the perimeter of
the given rectangle.