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You have completed JavaScript Basics!
You have completed JavaScript Basics!
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Every application that you interact with provides ways for its users to give it information. Learn how to use 'prompt()' to capture dynamic input from your site users.
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Earlier you learn techniques for
0:00
outputting information that
you provided the program.
0:02
For example, an
0:05
alert dialog and printing a message to
the JavaScript console with console.log.
0:06
So far, it's been just you manually
feeding the program input,
0:10
which isn't all too useful.
0:14
Just about every application that
you interact with provides ways for
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it to user to give it information.
0:19
For example, sign up for an account,
log in, create a profile, and so on.
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You can capture dynamic input from your
site users in a number of different ways.
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For instance, when a user fills out a form
field, you can capture what they type.
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Browsers also provide a simple way
of capturing input with JavaScript,
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let's see how it works.
0:37
All right,
it's time to learn a new command.
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This time, open the prompt.js
file inside your js folder and
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update the script tag in index.html so
that it points to prompt.js.
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The prompt command gives you a way to
collect information from a site user.
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For example, you can ask a question and
get a response.
1:01
In your prompt.js file,
start by typing prompt,
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immediately followed by a set
of parentheses and a semicolon.
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Notice again the parentheses, which now
you know means that this is a method.
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In fact, from now on, we can refer to
these types of commands, including
1:16
console.log and alert, as methods,
which is what they're commonly called.
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You use the prompt method
to ask a question or
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prompt the user to input some text.
1:27
Like the alert method,
you provided a message as a string.
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For example, what is your name?
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I'll save the file.
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When I refresh the browser,
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notice how prompt displays
a dialog box with the question.
1:42
Much like the alert method,
only this time,
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there's a text field where a user
can type something into it.
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I'll type Guil and click OK.
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But what happens to the text I just typed?
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As it turns out, the browser
captures the user's response and
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gives it back to the program.
2:02
In programming speak,
we say that prompt returns a value.
2:04
Knowing that, we can store that return
value variable, in other words,
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we can capture the user's
input to use in our program.
2:12
For example,
declare a const variable named name and
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assign it the prompt method.
2:21
And now there are a couple of ways to see
what get stored in this new variable.
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First, we can use an alert.
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Back in the browser, I'll refresh the page
then type Guil into the dialog box.
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When I click OK, notice how Guil
appears in the alert dialog.
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The prompt method gives you back the
user's response, or the text they entered.
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So notice how a variable is
really useful in this case.
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By storing the name in a variable,
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each person who visits this webpage gets
a different response, customized to them.
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You can also use console.log to
write the variable to the console.
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I'll change alert to console.log.
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And while your site users probably
won't look at the console,
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it's still a great place for you, the
programmer to send messages to yourself.
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You can use it to look into
your program at any point.
3:20
Here we're using the console to see what's
inside the name variable at this point
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in the program.
3:29
And we've been doing a lot of that so
far in this course.
3:30
For example, earlier we used the console
to debug errors in our code.
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And we've also used it to check string and
number values stored in variables.
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So as you learned,
the prompt method provides a quick and
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easy way to capture user input.
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So it's a useful feature for learning.
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And later, you'll learn how to
use information captured with
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prompt in a program.
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Although you might see prompt dialog
boxes used on the web, in reality,
3:52
you'd capture input
using fields in a form.
3:56
I'm not gonna cover that in this course,
but
3:59
you'll learn how to capture input
with forms in a later course.
4:01
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