# GvaScript.ChoiceList

Dropdown list of choices with navigation

### Table of contents

NAME
SYNOPSIS
DESCRIPTION
BEHAVIOUR
CONSTRUCTOR
Choices
Options
METHODS
fillContainer
EVENTS
onHighlight
onPing
onCancel

## NAME

GvaScript.ChoiceList - Dropdown list of choices with navigation

## SYNOPSIS

      var choiceList = new GvaScript.ChoiceList(["foo", "bar", "buz"]);
      choiceList.fillContainer($('myChoiceDiv'));

## DESCRIPTION

Displays a list of "choices", handles navigation in those choices, and generates events when a choice is highlighted, then selected, or when the list display is cancelled.

At any moment the choiceList is bound to maximum one "container", and highlights exactly one choice in the list.

## BEHAVIOUR

Once a choice list is displayed, the user can move the mouse over the list, thus highlighting various choices; then click on the highlighted choice to select it. Alternatively, the user can navigate the list with keys `DOWN`, `UP`, `HOME`, `END`, and then use either `RETURN` (for selecting) or `ESCAPE` (for cancelling).

## CONSTRUCTOR

      var choiceList = new GvaScript.ChoiceList(choices, options);

### Choices

The choice list must be an array. Each item in the list is either

- a plain string

  this string will be displayed in the choice list

- an inline object

  this object is supposed to have a `label` property, which will be displayed in the choice list. Actually, this is the default name for the property; it can be changed in the constructor options.

  The `label` property may contain rich HTML, i.e. including formatting tags.

### Options

The options to construct an choiceList object are :

- labelField

  Name of the field that contains the HTML to display (default is `label`).

- idForChoices

  Prefix that will be used to generate ids for choice elements in the generated HTML. The default is `CL_choice`, so choice elements will have ids `CL_choice.0`, `CL_choice.1`, etc.

- keymap

  If defined, the choiceList will add rules to the supplied keymap, instead of creating a new one.

- scrollCount

  How many items to skip when hitting the `PAGE_UP` or `PAGE_DOWN` keys. Default is 5

- classes

  Classes that will be assigned to choice elements in the generated HTML. Possible classes are `choiceItem` (default value `CL_choiceItem`) and `choiceHighlight` (default value `CL_highlight`).

- htmlWrapper

  Callback function for generating HTML for the choiceList. This function is called with some pre-built HTML containing all current choices; the wrapper has a chance to modify that HTML for example for adding classes, borders or table headers. Default is the identity function.

- choiceItemTagName

  HTML tag name for generating a choice entry in the choice list. Default is "div". Set it to "tr" if you want the choice list to be displayed as a table (but then you also have to open and close the table within the `htmlWrapper` callback).

## METHODS

### fillContainer

      choiceList.fillContainer(someDiv);

This method generates HTML from the choice list, and inserts it in the `innerHTML` of the supplied container; furthermore, it registers a keymap on that container in order to manage navigation from keyboard (`DOWN`, `UP`, etc.).

## EVENTS

### onHighlight

This event is triggered when a choice in the list is highlighted. The event handler may use `event.index` to know the index of the highlighted choice.

### onPing

This event is triggered when a choice in the list is "ping-ed", i.e. either by clicking or by pressing the `RETURN` key. Usually this means "select", but it is up to the event handler to decide how to interpret the event. The event handler may use `event.index` to know the index of the ping-ed choice.

### onCancel

This event is triggered when the user presses the `ESCAPE` key.