Programmer's Guide > Interfaces > Application interface > prompt method
  
prompt method
Displays a modal dialog box with the specified message prompt, a text input field, and OK and Cancel buttons.
prompt(prompt [, value [, title]] )
Parameters
Stringprompt
Specifies the message to display in the dialog box
Stringvalue
[optional] Specifies the initial value displayed in the text input field.
Stringtitle
[optional] Specifies the dialog box title. If omitted, the title defaults to "Prompt".
Returns
String. Returns the string in the text input field if the user clicks OK. Returns null if the user clicks Cancel.