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JavaScript Prompt Input: A Quick Guide

HomeBlogWeb DevelopmentJavaScript Prompt Input: A Quick Guide

JavaScript Prompt Input: A Quick Guide

Blog Author

Arpa Chatterjee

Published

05th Sep, 2023

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12 Mins

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JavaScript is a dynamic programming language for the computer. As a component of web pages, it enables client-side scripts to interact with the user and create dynamic pages. It is an object-oriented interpreted programming language. The best part about this is that you can learn Node.js from scratch.

There is speculation that Netscape renamed JavaScript from LiveScript because of the enthusiasm produced by Java. LiveScript was the original name of JavaScript when it first appeared in Netscape 2.0 in 1995. Netscape, Internet Explorer, and other web browsers include the language's general-purpose core.

The ECMA-262 Specification specified a standard version of the JavaScript core language.

Programming with JavaScript is fast and easy since it is an interpreted language.
Built for network-centric software development
Integral and complementary to Java.
HTML-compatibility and HTML-integration.
Accessible from any computer or mobile device

Prompt() displays a dialog with an optional message that asks the user to enter some content. If the user wishes to submit a value before visiting a page, this is the most common method. To know how to take input in javascript, keep reading.

User Input From a Prompt in JavaScript: A Quick Guide

What is the JavaScript Prompt() Method?

People are asking, “How to take input from a user in JavaScript?” Using JavaScript's prompt() function, you may show a prompt box that asks the user for their input. Typically, it gathers information from the user before the page is loaded. It doesn't need the window prefix to be used. This prompt box asks for a choice between 'OK' and 'Cancel.'

The prompt() function, which accepts two parameters, is used to show the message box. Textbox label and textbox default string are two separate arguments. There are just two options in the dialogue box: OK and Cancel. If the user-provided a string, it will be returned instead of null. The box returns the value entered by the user when they hit "OK." If you click "Cancel," it returns nil.

The user is compelled to read the message in the prompt box. It's best not to overuse this strategy because it prevents the user from accessing other portions of the site until the box is closed.

Text submitted by the user is returned as a string or null.

Syntax:

As a result of (message, default)

Text to be shown to the user in a message.

It is optional and may be removed if the prompt window does not include anything to display.

In the text input area, the default value is a shown string. In addition, it is possible.

Example:

<!DOCTYPE html>
<html>
<head>
    <title>
        Window prompt() Method
    </title>
</head>
<body style="text-align: center;">
    <h1 style="color:green;">
        GeeksforGeeks
    </h1>
    <h2>
        Window prompt() Method
    </h2>
 <button onclick="geek()">
        Click me!
    </button>
    <p id="g"></p>
  <script>
        function geek() {
            var doc = prompt("Please enter some text",
                "GeeksforGeeks");
            if (doc != null) {
                document.getElementById("g").innerHTML =
                    "Welcome to " + doc;
            }
        }
    </script>
</body>
</html>

User Input From Browser Console

Prompting the user for information may be done using JavaScript. The following command may be used to test out how to take user input in JavaScript in the JS console:

"What is your name?" and a response

In your browser window, a text box opens after pressing Return or Enter, as illustrated above.

The pop-up window vanishes once you input your name and click OK, and the value you provided in the same shows in the console, as seen above.

This is fine if you only want to collect data and repeat it like a parrot. Then, what if you’re going to do anything with the user's data? You'll need to save it as a variable to do this.

Create a new variable followed by the equal sign to hold user-entered data. Then, you respond to the question with the following sentence.

Username: var username = prompt("what is your name?");

If you want to know how to take input in node js, keep reading. In the same way as previously, pressing Return or Enter brings up a pop-up window in your browser. JavaScript Console prints out undefined after entering your name in the pop-up window, indicating that the statement is complete and there is nothing else to do.

Type the variable name into the console to view the value you just typed. In this example, JavaScript reacts by returning the value of the variable.

Input From the Browser Console of a User

You must utilize the browser's prompt() function if you want the browser to ask for user input. You may receive user input in the form of a string and save it in a variable using the following Method:

const input is equal to prompt();

This function additionally takes a string as an extra piece of information about what the program expects in terms of input. To ask for a user name, the following code is used:

"What's your name?" is a prompt for input.

The name you entered is $input.

The result is shown in an alert() message. Depending on your needs, you can format the line content as a question or a tip.

Using the NodeJS Console to Get User Input

The given deadline module must be used to take user input from the NodeJS console. The following module commands, such as need(), are available to you:

Const readline = require("readline").

Then, you need to create the interface linked to the input stream and use it to make decisions. Make use of the readline to your advantage. A create interface() Method is used to build an interface and supply parameters as object arguments.

Process. Stdin and process. Stdout must be written with input and output.

Here's an example of how to implement a readline user interface.

if readline is a const, then it should be required.
createInterface(ql) = readline.createInterface(
process.stdin is the input.
Process.stdout is the output.
});

The question() function must be invoked on the interface instance allocated to the Q1 variable in the code above to solicit user feedback.

There are two inputs for the question() method.
You may type in a string of questions here.

When a response is received, this callback function is called, and the response is sent along to the function.

The callback function may be sent in place of the argument object as the second parameter.

Finally, the q1.close() method in the callback function may be used to shut the q1 interface.
arr.js:
if reading is a const, then it should be required.
constant q1 = readline.create interface
process. Stdin is the input.
Process. stdout is the output.
});
"Where do you live?" function (response)
"Oh, so you reside in the city of $response."
The interface has been closed.
q1.close();
});
Using the prompt-sync Module to Get User Input from NodeJS
NPM or Yarn may be used to install the prompt-sync Module.
use npm to set up "prompt-sync."
or
Yarn adds quick sync.
Finally, the need() function is needed for the prompt-sync Module.
You can see the code here.
pm.js:
require("prompt-sync")();
prompt("Where do you live?"); const input;
'Oh, so you reside in $input';

For this approach to work, the Node instance must wait for input before moving on to the following line of code. Also, a full stack java developer course can be helpful if you want to know more.

User Input From Node.js Console

Using Node.js CLI, how can I make it interactive?

Using the readline module in Node.js, you can obtain input from a readable stream like the process. Stdin stream is the terminal input during the execution of a Node.js application.

When the user enters their name and pushes enter, this code sends a welcome to the user. But how to take input in javascript from the console?

In the question() function, the first argument (a question) is shown, and the user is prompted to answer it. When the enter key is pushed, the callback function is invoked. We close the readline interface in this callback function.

Please check out the readline documentation mentioned above for more options.

It's better to display a * sign instead of echoing the password if you need to demand one. Use the readline-sync package, which has a comparable API and takes care of this for you by default. For a more comprehensive and abstract solution, check out the Inquirer.js package.

npm install inquirer may be used to set it up, and then the code shown above can be used as follows:

consisting of queries =
{
"input" as the type
'name' is the name
"What's your name?" is the message.
},
];
inquirer.prompt(questions).
After that, the results are as follows:
log('Hi $answers.name!'), console.log('
});

For example, you can use Inquirer.js to ask for numerous options, radio buttons, etc. It's essential to be aware of all the options available, particularly those supplied by Node.js' built-in libraries, but Inquirer.js is the best option for using CLI input to its full potential.

User Input From Node.js Console with prompt-sync Module

Synchronized Input

Node.js offers sophisticated capabilities to interface with the computer filesystem, operate web servers, and construct terminal apps to execute JavaScript code outside the browser. Node does these processes asynchronously, which means that getting user input from a terminal is not as straightforward as executing a get input() method. Using a practical Node module, we'll teach you how to get around it (as well as other helpful tips and tactics for processing user input).

Input Processing

In addition to the built-in process object and reading module, Node.js gives several options for handling interactions. Callback functions are a significant part of these technologies, making them difficult to understand when you first start using them.

'readline' is required to be a const readline.
create an interface({
process. Stdin is the input.
the stdout output of the procedure
});

The query 'Who are you?' is readline. question

In the terminal, report "Hey there, $name!"

reading.close();

});

Readline. Question () and the callback function must be called every time an input field is needed to be used. This works as intended, but it is cumbersome and requires a lot of boilerplate. There is a more straightforward approach, whatever your JavaScript programming level or how fast you want to get an interactive script up and running.

Prompt-sync may be used to sync up with other applications.

A Node module called prompt-sync may be used instead of the callback-based syntax.

Node and NPM should be installed.

In the terminal, type npm install prompt-sync.

After ""need," there is an additional () (). So, to receive your prompting function, you need to call the function that makes them prompt-sync.

Once you’ve loaded the prompt-sync module and called it, using it to retrieve user input is relatively straightforward:

const prompt = require('prompt-sync')();
prompt('What is your name?') is a constant name.
(console.log "Hello there, $name")

It's simple to keep the user response returned by the prompt() Method as an object in a variable. The value is stored in the name variable, which is then repeated to the user on the following line.

Allowing Users to Leave

Ctrl + C is the default way to leave most terminal applications. This sends a SIGINT message, or "signal interrupt," indicating that the user wishes to terminate the program. When using prompt-sync, add a configuration object with SIGINT: true to ensure that your users may quit the program at any time:

"prompt-sync" is a requirement for the prompt.
Mathematical Problem Solving

Because every user input is received as a String, you must convert it to integers before using it:

numeric constants are used in the following way:
When prompted, type in the following numeric value:
Your number multiplied by four results in this:
console.log(Number(num) + 4) ;

For next steps, check out our blog posts about directory in Node.js.

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Conclusion

Hope now you know how to take multiple input from user in javascript. The prompt() function shows a dialog with an optional message urging the user to type some content. It is typically used if the user wishes to input a value before visiting a page. It returns a string containing the text supplied by the user, or null. Knowledgehut learn node js from scratch can be a really good option if you want to know more on this topic.

Frequently Asked Questions (FAQs)

1. How can I ask for input in JS?

For example, in JavaScript, the prompt() Method may ask the user for information. The text shown to the user is sent in as a parameter. When the user hits "OK," the input value is returned to them. So that we may utilize the information later, we usually save the user input as a variable.

2. How do I prompt user input?

The prompt() function shows a dialog box where the user is prompted to provide their information. If the user selects "OK," the prompt() function returns the input value; otherwise, it returns null.

3. How can I use a prompt in JavaScript?

Using JavaScript's prompt() function, the user is greeted with a prompt box that asks for their input. Typically, it gathers information from the user before the website loads. It doesn't need the window prefix to be used. To continue, we must click "OK" or "Cancel" on the prompt window that appears.

4. What is the use of prompt in JavaScript?

The prompt() function shows a dialog box where the user is prompted to provide their information. If the user selects "OK," the prompt() function returns the input value; otherwise, it returns null.

5. Can I get user input in JavaScript?

Arpa Chatterjee

Author

Arpa Chaterjee is the founder of Digital Web Infotech. On a busy day at work he provides top-quality services in the domains of web development and digital marketing. His USPs are clients based on mutual trust, transparency, and integrity.

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