nsIPromptService

This interface can be used to display simple dialogs. Its methods should be used in privileged code instead of DOM window.alert, window.confirm, and other similar functions.
Inherits from: nsISupports Last changed in Gecko 1.7.5

You can define access keys (or keyboard shortcuts) for buttons by including an ampersand ("&") in front of the character that should be the access key for that button. If you need to include an ampersand in the button's text, use two of them, like this: "&&".

Note: Some of these interface methods use out and inout parameters. In C++, out parameters are pointers. For JavaScript, they are extra work, as you can't use an out parameter directly. You need to wrap them in a temporary object, which can be either empty or have a value property set to the out parameter type. For more information on out parameters and JavaScript refer to Working with out parameters.

Implemented by: @mozilla.org/embedcomp/prompt-service;1. To get an instance, use:

var promptService = Components.classes["@mozilla.org/embedcomp/prompt-service;1"]
                              .getService(Components.interfaces.nsIPromptService);

Method overview

void alert(in nsIDOMWindow aParent, in wstring aDialogTitle, in wstring aText);
void alertCheck(in nsIDOMWindow aParent, in wstring aDialogTitle, in wstring aText, in wstring aCheckMsg, inout boolean aCheckState);
boolean confirm(in nsIDOMWindow aParent, in wstring aDialogTitle, in wstring aText);
boolean confirmCheck(in nsIDOMWindow aParent, in wstring aDialogTitle, in wstring aText, in wstring aCheckMsg, inout boolean aCheckState);
PRInt32 confirmEx(in nsIDOMWindow aParent,in wstring aDialogTitle,in wstring aText, in unsigned long aButtonFlags,in wstring aButton0Title, in wstring aButton1Title,in wstring aButton2Title,in wstring aCheckMsg, inout boolean aCheckState);
boolean prompt(in nsIDOMWindow aParent, in wstring aDialogTitle, in wstring aText, inout wstring aValue, in wstring aCheckMsg, inout boolean aCheckState);
boolean promptUsernameAndPassword(in nsIDOMWindow aParent, in wstring aDialogTitle, in wstring aText, inout wstring aUsername, inout wstring aPassword, in wstring aCheckMsg, inout boolean aCheckState);
boolean promptPassword(in nsIDOMWindow aParent, in wstring aDialogTitle, in wstring aText, inout wstring aPassword, in wstring aCheckMsg, inout boolean aCheckState);
boolean select(in nsIDOMWindow aParent, in wstring aDialogTitle, in wstring aText, in PRUint32 aCount, [array, size_is(aCount)] in wstring aSelectList, out long aOutSelection);

Constants

The following flags are combined to form the aButtonFlags parameter passed to confirmEx. All flags are defined as unsigned long constants and can be accessed as Components.interfaces.nsIPromptService.flagname from JavaScript and as nsIPromptService::flagname from C++.

Button position flags

On Linux and Mac, button 2 is on the left of the prompt, while buttons 1 and 0 are on the right. On Windows and OS/2, the buttons are centred in the order 0, 2, 1.

Constant Value Description
BUTTON_POS_0 1 This is usually the button used to confirm the prompt. It typically has the label "OK", "Yes", or "Save".
BUTTON_POS_1 256 This is the button used to cancel the prompt. It typically has the label "Cancel" or "No". It is equivalent to pressing the Escape key (or Cmd+. on the Mac), or closing the window through the OS controls.
BUTTON_POS_2 65536 This button can be used to give the user a choice of options, but still allowing the user to cancel the prompt. For instance, it might have the label "Don't Save".

Button title flags

These flags are used along with Button position flags to set the labels of buttons in the prompt.

Constant Value Description
BUTTON_TITLE_OK 1 These flags are used to select standard labels from the user's current locale.
BUTTON_TITLE_CANCEL 2
BUTTON_TITLE_YES 3
BUTTON_TITLE_NO 4
BUTTON_TITLE_SAVE 5
BUTTON_TITLE_DONT_SAVE 6
BUTTON_TITLE_REVERT 7
BUTTON_TITLE_IS_STRING 127 This flag indicates that the label is passed as a separate string. Use this for labels that don't match one of the constants above.

Button default flags

These flags are used to select which button is the default.

Constant Value Description
BUTTON_POS_0_DEFAULT 0  
BUTTON_POS_1_DEFAULT 16777216  
BUTTON_POS_2_DEFAULT 33554432  

BUTTON_DELAY_ENABLE

BUTTON_DELAY_ENABLE causes the buttons to be initially disabled. They are enabled after a timeout expires. The implementation may interpret this loosely, as the intent is to ensure that the user does not click through a security dialog too quickly. Strictly speaking, the implementation could choose to ignore this flag. A delay can be useful not only to give the user more time to think before acting, but also as a countermeasure against malicious web sites that intentionally create a race condition whereby the user intends to click or type a key responding, for example, to the web site's prompt but the security dialog pops up unexpectedly and its button is unintentionally activated.

Constant Value Description
BUTTON_DELAY_ENABLE 67108864  

Standard Buttons flags

Constant Value Description
STD_OK_CANCEL_BUTTONS 513

selects the standard set of OK/Cancel buttons.

(BUTTON_TITLE_OK *BUTTON_POS_0) +(BUTTON_TITLE_CANCEL * BUTTON_POS_1)
STD_YES_NO_BUTTONS 1027

selects the standard set of Yes/No buttons.

(BUTTON_TITLE_YES *BUTTON_POS_0) +(BUTTON_TITLE_NO * BUTTON_POS_1)

Methods

alert()

alert shows an alert dialog with an OK button. It works the same way as window.alert, but accepts a title for the dialog. You should use this method instead of window.alert in chrome code.

void alert(
  in nsIDOMWindow aParent,
  in wstring aDialogTitle,
  in wstring aText
);
Parameters
aParent
The parent window for the dialog, or null, in which case the parent window will be nsIWindowWatcher.activeWindow.
aDialogTitle
Text to appear in the title of the dialog.
aText
Text to appear in the body of the dialog.

See also the alert_example.

alertCheck()

Shows an alert dialog with an OK button and a labeled checkbox.

void alertCheck(
  in nsIDOMWindow aParent,
  in wstring aDialogTitle,
  in wstring aText,
  in wstring aCheckMsg,
  inout boolean aCheckState
);
Parameters
aParent
The parent window for the dialog. If set to null the parent window will be nsIWindowWatcher.activeWindow.
aDialogTitle
Text to appear in the title of the dialog.
aText
Text to appear in the body of the dialog.
aCheckMsg
Text to appear with the checkbox.
aCheckState
Contains the initial checked state of the checkbox when this method is called and the final checked state after this method returns. If you call this method from JavaScript you need to wrap this argument in an object with its 'value' property set to a boolean (or use an empty object).

See also the alertCheck_example.

confirm()

Shows a dialog with OK and cancel buttons.

boolean confirm(
  in nsIDOMWindow aParent,
  in wstring aDialogTitle,
  in wstring aText
);
Parameters
aParent
The parent window for the dialog. If set to null the parent window will be nsIWindowWatcher.activeWindow.
aDialogTitle
Text to appear in the title of the dialog.
aText
Text to appear in the body of the dialog.
Return value
true for OK, false for Cancel

See also the confirm_example.

confirmCheck()

Shows a dialog with OK and Cancel buttons and a labeled checkbox.

See also the confirm_example.

boolean confirmCheck(
  in nsIDOMWindow aParent,
  in wstring aDialogTitle,
  in wstring aText,
  in wstring aCheckMsg,
  inout boolean aCheckState
);
Parameters
aParent
The parent window for the dialog. If set to null the parent window will be nsIWindowWatcher.activeWindow.
aDialogTitle
Text to appear in the title of the dialog.
aText
Text to appear in the body of the dialog.
aCheckMsg
Text to appear with the checkbox.
aCheckState
Contains the initial checked state of the checkbox when this method is called and the final checked state after this method returns. If you call this method from JavaScript you need to wrap this argument in an object with its 'value' property set to a boolean (or use an empty object).
Return value
true for OK, false for Cancel

confirmEx()

Puts up a dialog with up to 3 buttons and an optional, labeled checkbox.

The Buttons are numbered 0 - 2. The implementation can decide what order the buttons appear in, and it may not be simply right-to-left (2, 1, 0) or left-to-right (0, 1, 2). See bug 624043 for more on this. Button 0 is the default button unless one of the Button Default Flags is specified (see Button default flags).

A button may use a predefined title, specified by one of the Button Title Flags values. Each title value can be multiplied by a position value to assign the title to a particular button. If BUTTON_TITLE_IS_STRING is used for a button, the string parameter for that button will be used. If the value for a button position is zero, the button will not be shown.

The following example creates a Dialog with an OK button and a custom button description.

aButtonFlags = (BUTTON_POS_0) * (BUTTON_TITLE_OK) +
(BUTTON_POS_1) * (BUTTON_TITLE_IS_STRING) +
BUTTON_POS_1_DEFAULT;

confirmEx always returns 1 if the user closes the window using the close button in the titlebar! bug 345067
PRInt32 confirmEx(
  in nsIDOMWindow  aParent,
  in wstring aDialogTitle,
  in wstring aText,
  in unsigned long aButtonFlags,
  in wstring aButton0Title,
  in wstring aButton1Title,
  in wstring aButton2Title,
  in wstring aCheckMsg,
  inout boolean aCheckState
);
Parameters
aParent
The parent window for the dialog. If set to null the parent window will be nsIWindowWatcher.activeWindow.
aDialogTitle
Text to appear in the title of the dialog.
aText
Text to appear in the body of the dialog.
aButtonFlags
aButtonFlags is a combination of Button flags as described in Using the button flags below.
aButton0Title
caption displayed for button 0 if(BUTTON_TITLE_IS_STRING*BUTTON_TITLE_POS_0) flags are set in aButtonFlags
aButton1Title
caption displayed for button 1 if(BUTTON_TITLE_IS_STRING*BUTTON_TITLE_POS_1) flags are set in aButtonFlags
aButton2Title
caption displayed for button 2 if(BUTTON_TITLE_IS_STRING*BUTTON_TITLE_POS_2) flags are set in aButtonFlags
aCheckMsg
Text to appear with the checkbox. Null if no checkbox is displayed.
aCheckState
Contains the initial checked state of the checkbox when this method is called and the final checked state after this method returns. If you call this method from JavaScript you need to wrap this argument in an object with its 'value' property set to a boolean (or use an empty object).
Return value
index of the button pressed

prompt()

Shows a dialog with an edit field and an optional, labeled checkbox.

See also the prompt_example.

boolean prompt(
  in nsIDOMWindow aParent,
  in wstring aDialogTitle,
  in wstring aText,
  inout wstring aValue,
  in wstring aCheckMsg,
  inout boolean aCheckState
);
Parameters
aParent
The parent window for the dialog. If set to null the parent window will be nsIWindowWatcher.activeWindow.
aDialogTitle
Text to appear in the title of the dialog.
aText
Text to appear in the body of the dialog.
aValue
Contains the default value for the dialog field when this method is called (null value is ok). Upon return, if the user pressed OK, then this parameter contains a newly allocated string value. Otherwise, the parameter's value is unmodified. If you call this method from JavaScript you need to wrap this argument in an object with its 'value' property set to a string (or use an empty object).
aCheckMsg
Text to appear with the checkbox. If null, checkbox will not be shown.
aCheckState
Contains the initial checked state of the checkbox when this method is called and the final checked state after this method returns. If you call this method from JavaScript you need to wrap this argument in an object with its 'value' property set to a boolean (or use an empty object).
Return value
true for OK, false for Cancel

promptUsernameAndPassword()

Shows a dialog with an edit field, a password field, and an optional, labeled checkbox.

See also the promptUsernameAndPassword_example.

boolean promptUsernameAndPassword(
  in nsIDOMWindow aParent,
  in wstring aDialogTitle,
  in wstring aText,
  inout wstring aUsername,
  inout wstring aPassword,
  in wstring aCheckMsg,
  inout boolean aCheckState
);
Parameters
aParent
The parent window for the dialog. If set to null the parent window will be nsIWindowWatcher.activeWindow.
aDialogTitle
Text to appear in the title of the dialog.
aText
Text to appear in the body of the dialog.
aUsername
Contains the default value for the username field when this method is called (null value is ok). Upon return, if the user pressed OK, then this parameter contains a newly allocated string value. Otherwise, the parameter's value is unmodified. If you call this method from JavaScript you need to wrap this argument in an object with its 'value' property set to a string (or use an empty object).
aPassword
Contains the default value for the password field when this method is called (null value is ok). Upon return, if the user pressed OK, then this parameter contains a newly allocated string value. Otherwise, the parameter's value is unmodified. If you call this method from JavaScript you need to wrap this argument in an object with its 'value' property set to a string (or use an empty object).
aCheckMsg
Text to appear with the checkbox. If null, checkbox will not be shown.
aCheckState
Contains the initial checked state of the checkbox when this method is called and the final checked state after this method returns. If you call this method from JavaScript you need to wrap this argument in an object with its 'value' property set to a boolean (or use an empty object).
Return value
true for OK, false for Cancel

promptPassword()

Shows a dialog with a password field and an optional, labeled checkbox.

See also the promptPassword_example.

boolean promptPassword(
  in nsIDOMWindow aParent,
  in wstring aDialogTitle,
  in wstring aText,
  inout wstring aPassword,
  in wstring aCheckMsg,
  inout boolean aCheckState
);
Parameters
aParent
The parent window for the dialog. If set to null the parent window will be nsIWindowWatcher.activeWindow.
aDialogTitle
Text to appear in the title of the dialog.
aText
Text to appear in the body of the dialog.
aPassword
Contains the default value for the password field when this method is called (null value is ok). Upon return, if the user pressed OK, then this parameter contains a newly allocated string value. Otherwise, the parameter's value is unmodified. If you call this method from JavaScript you need to wrap this argument in an object with its 'value' property set to a string (or use an empty object).
aCheckMsg
Text to appear with the checkbox. If null, checkbox will not be shown.
aCheckState
Contains the initial checked state of the checkbox when this method is called and the final checked state after this method returns. If you call this method from JavaScript you need to wrap this argument in an object with its 'value' property set to a boolean (or use an empty object).
Return value
true for OK, false for Cancel

select()

Shows a dialog box with a list box of strings from which the user may make a single selection.

See also the select_example.

boolean select(
  in  nsIDOMWindow aParent,
  in  wstring       aDialogTitle,
  in  wstring       aText,
  in  PRUint32     aCount,
  [array, size_is(aCount)] in wstring aSelectList,
  out long         aOutSelection
);
aParent
The parent window for the dialog. If set to null the parent window will be nsIWindowWatcher.activeWindow.
aDialogTitle
Text to appear in the title of the dialog.
aText
Text to appear in the body of the dialog.
aCount
Length of the aSelectList array parameter.
aSelectList
List of strings to display.
aOutSelection
Contains the index of the selected item in the list when this method returns true. If you call this method from JavaScript, this argument is wrapped in an object with an attribute named 'value' which holds the selected index.
Return value
true for OK, false for Cancel

Example code

 

alert example

alert displays a simple dialog.

var prompts = Components.classes["@mozilla.org/embedcomp/prompt-service;1"]
                        .getService(Components.interfaces.nsIPromptService);

prompts.alert(null, "Title of this Dialog", "Hello! You have now been alerted.");

alertCheck example

alertCheck dispays a dialog with a checkbox.

var prompts = Components.classes["@mozilla.org/embedcomp/prompt-service;1"]
                        .getService(Components.interfaces.nsIPromptService);

var check = {value: false};                      // default the checkbox to false

prompts.alertCheck(null, "Title of this Dialog", "Hello! You have now been alerted.",
                   "And this is a checkbox", check);

// check.value is now true if the box was checked and false if the box was cleared

confirm example

confirm displays a dialog with OK/Cancel.

var prompts = Components.classes["@mozilla.org/embedcomp/prompt-service;1"]
                        .getService(Components.interfaces.nsIPromptService);

var result = prompts.confirm(null, "Title of this Dialog", "Are you sure?");

// result is now true if OK was clicked, and false if cancel was clicked

confirmCheck example

confirmCheck displays a dialog with OK/Cancel and a checkbox

var prompts = Components.classes["@mozilla.org/embedcomp/prompt-service;1"]
                        .getService(Components.interfaces.nsIPromptService);

var check = {value: true};                   // default the checkbox to true

var result = prompts.confirmCheck(null, "Title of this Dialog", "Are you sure?",
                                  "Don't ask again", check);

// check.value is now true if the box was checked AND OK was pressed, false if
// the box was cleared AND OK was pressed, and is the default of true if Cancel was pressed.

confirmEx example

confirmEx displays a dialog with up to 3 buttons and an optional checkbox.

var prompts = Components.classes["@mozilla.org/embedcomp/prompt-service;1"]
                        .getService(Components.interfaces.nsIPromptService);

var check = {value: false};                  // default the checkbox to false

var flags = prompts.BUTTON_POS_0 * prompts.BUTTON_TITLE_SAVE +
            prompts.BUTTON_POS_1 * prompts.BUTTON_TITLE_IS_STRING  +
            prompts.BUTTON_POS_2 * prompts.BUTTON_TITLE_CANCEL;
// This value of flags will create 3 buttons. The first will be "Save", the
// second will be the value of aButtonTitle1, and the third will be "Cancel"

var button = prompts.confirmEx(null, "Title of this Dialog", "What do you want to do?",
                               flags, "", "Button 1", "", null, check);

// The checkbox will be hidden, and button will contain the index of the button pressed,
// 0, 1, or 2.

prompt example

prompt displays a dialog with an edit field.

var prompts = Components.classes["@mozilla.org/embedcomp/prompt-service;1"]
                        .getService(Components.interfaces.nsIPromptService);

var check = {value: false};                  // default the checkbox to false

var input = {value: "Bob"};                  // default the edit field to Bob

var result = prompts.prompt(null, "Title", "What is your name?", input, null, check);

// result is true if OK is pressed, false if Cancel. input.value holds the value of the edit field if "OK" was pressed.

promptUsernameAndPassword example

promptUsernameAndPassword displays a dialog with an edit field, password field, and optionally a checkbox.

var prompts = Components.classes["@mozilla.org/embedcomp/prompt-service;1"]
                        .getService(Components.interfaces.nsIPromptService);

var username = {value: "user"};              // default the username to user

var password = {value: "pass"};              // default the password to pass

var check = {value: true};                   // default the checkbox to true

var result = prompts.promptUsernameAndPassword(null, "Title", "Enter username and password:",
                                               username, password, "Save", check);

// result is true if OK was pressed, false if cancel was pressed. username.value,
// password.value, and check.value are set if OK was pressed.

promptPassword example

promptPassword displays a dialog with a password field and an optional checkbox.

var prompts = Components.classes["@mozilla.org/embedcomp/prompt-service;1"]
                        .getService(Components.interfaces.nsIPromptService);

var password = {value: "pass"};              // default the password to pass

var check = {value: true};                   // default the checkbox to true

var result = prompts.promptPassword(null, "Title", "Enter password:", password, null, check);

// result is true if OK was pressed, false if cancel was pressed. password.value is
// set if OK was pressed. The checkbox is not displayed.

select example

select displays a dialog with a listbox of choices.

var prompts = Components.classes["@mozilla.org/embedcomp/prompt-service;1"]
                        .getService(Components.interfaces.nsIPromptService);

var items = ["Hello", "Welcome", "Howdy", "Hi", ":)"]; // list items

var selected = {};

var result = prompts.select(null, "Title", "What greeting do you want?", items.length,
                            items, selected);

// result is true if OK was pressed, false if cancel. selected is the index of the item array
// that was selected. Get the item using items[selected.value].

See also

Document Tags and Contributors

Contributors to this page: trevorh
Last updated by: trevorh,