[Chapter 21] Reference: Window.prompt()
Author: David Flanagan
Date: Fri Aug 29 11:21:31 1997

#

| Chapter 21 JavaScript Reference |

# Window.prompt() Method

## Name

Window.prompt() Method---get string input in a dialog

## Availability

Navigator 2.0, Internet Explorer 3.0

## Synopsis

    window.prompt(message)
    window.prompt(message, default)

### Arguments

`message`

  The plain text (not HTML) string to be displayed in the dialog. It should ask the user to enter the information you want. On Windows platforms, only one line messages are allowed.

`default`

  An optionally specified string or integer which will be displayed as the default input in the dialog. If `null` is specified, or if this argument is not passed at all, then `prompt()` displays the string "<undefined>" as the default value. Pass the empty string (`""`) to make `prompt()` display an empty input box.

### Returns

The string entered by the user, or the empty string if the user did not enter a string, or `null` if the user clicked Cancel.

## Description

The `prompt()` method displays the specified `message` in a dialog box that also contains a textual input field and OK, Clear, and Cancel buttons. Platform-dependent graphics in the dialog help to indicate to the user that her input is desired.

The `default` argument specifies the text that initially appears in the input field. If `default` is `null`, or if this optional argument is not passed at all, then the initial text is "<undefined>". If `default` is the empty string (`""`) then the input field is initially empty. Otherwise, the input field displays the string or number that is passed as the `default`.

If the user clicks the Cancel button, `prompt()` returns `null`. If the user clicks the Clear button, `prompt()` erases any current text in the input field. If the user clicks the OK button, `prompt()` returns the value current value displayed in the input field. Note, however, that if the input field is displaying "<undefined>" because the `default` argument was `null` or unspecified, then `prompt()` returns the empty string and not the string "<undefined>". Also note that `prompt()` always returns the user's input as a string value, even if `default` was specified as a numeric value. If necessary, you can use `parseInt()` or `parseFloat()` to convert the returned string to a number.

The dialog box that is displayed by the `prompt()` method is modal--that is, it blocks all user input to the main browser window until the user dismisses the dialog by clicking on the OK or Cancel buttons. Since this method returns a value depending on the user's response to the dialog, JavaScript execution pauses in the call to `prompt(),` and subsequent statements are not executed until the user responds to the dialog.

## Usage

Note that the `question` displayed in the dialog is a string of plain text, not of formatted HTML. Unlike the message displayed by the `alert()` and `confirm()` methods, the message displayed by `prompt()` may only be a single line long on Windows platforms.

## See Also

"Window", "Window.alert()", "Window.confirm()"

Window.parent |  | Window.scroll()