Introduction to JavaScript prompt() method

The prompt() is a method of the window object. The prompt() method instructs the web browser to display a dialog with a text, text input field, and two buttons OK and Cancel.

The dialog prompts the user to enter some text and wait until the user either submits or cancels it. The following illustrates the syntax of the prompt() method:

Code language: JavaScript (javascript)

In this syntax:

• The message is a string to display. If you omit it, nothing will display on the dialog.
• The default is a string containing the default value of the text input field.

The result is a string that contains the text entered by the user or null.

Like alert() and confirm(), the prompt() is modal and synchronous. In other words, the code execution stops when the dialog is displayed and resumes after the dialog has been dismissed.

JavaScript prompt() examples

Let’s take some examples to see how the prompt() works.

1) Display a prompt dialog

The following example uses the prompt() to display a dialog that prompts users for their favorite programming languages:

Code language: JavaScript (javascript)

2) Convert a user input to a number

The result of the prompt() is a string. If you want to get the answer as a number, you should always cast the string into a number.

The following example uses prompt() to display a dialog that asks users for their ages. If users are 16 years old or above, they are eligible to join. Otherwise, they will not be.

Code language: PHP (php)

Summary

• The prompt() is a method of the window object.
• The prompt() shows a dialog that prompts the user to enter a text and wait until the user submit or cancel the dialog.
• The prompt() returns a string containing a string entered by the user or null if the user did not enter anything.