autocompletion on form input fields
GvaScript.Autocompleter - autocompletion on form input fields
In Javascript :
var autocompleter1 = new GvaScript.Autocompleter( "http::/some/url", {minimumChars : 2, strict : true, onBind : doSomething, onLeave : doSomethingElse} );
var autoCompleter2 = new GvaScript.Autocompleter( ["foo", "bar", ...], options);
var autoCompleter3 = new GvaScript.Autocompleter( [{label: "foo", value: "f", otherValue: 123}, {label: "bar", value: "b", otherValue: 456}, ...], options);
var autoCompleter4 = new GvaScript.Autocompleter( myCompletionFunction, options);
Then, in HTML :
<input onfocus="autoCompleter1.autocomplete(this)">
Component designed both as an "autocompleter" (anticipating
further key events by users) and as a replacement for HTML SELECT
form items.
An autocompleter instance encapsulates a datasource (which may be an inline object, a callback function or an Ajax request), together with some behavioral options (detailed below). That autocompleter may then be bound to one or several input fields in a form (but only one at a time), and will take care of capturing user input, navigating in the suggestion list, and filling the field with the chosen value.
An event model is associated with the autocompleter, so that client code can insert its own hooks to various steps of the autocompletion behaviour.
The list of suggestions may contain arbitrary HTML, including rich formatting options.
When the input field gets focus, the autocompleter starts listening
for key events. As soon as minimumChars
have been typed, or if the
user presses the DOWN
arrow key, the autocompleter gets a list of
suggestions from the datasource, and displays them in a dropdown list.
The dropdown list can be navigated through arrow keys. Selecting a
suggestion in the list is done either by a click, or by pressing the
RETURN
key (this is handled by the choiceList component of
GvaScript). Then the value of that suggestion fills the input field
value, the jsonValue
property of that field is set to whatever was
contained in the suggestion object, and the onComplete
event is
triggered.
A number of Variations on this behaviour may be controlled by the options described below.
var myAutocompleter = new GvaScript.Autocompleter(datasource, options);
A datasource may be
The string is taken as a base URL. Whenever a suggestion list is needed, the autocompleter will send an Ajax requests to that URL, concatenated with the current value in the associated field. So for example if we have
var ac = new GvaScript.Autocompleter("http://my/server/completion?search="); .. <input name="someInput" onfocus="ac.complete(this)">
and user has typed ab
in the input field, then an Ajax request
will be sent to http://my/server/completion?search=ab
.
The server should return a JSON array, in the format explained below.
That function will be called, with the current value of the field as single argument.
The array is taken as in-memory datasource. The returned suggestion
list is either the complete array (when options.ignorePrefix
is true)
or just the list of items that are prefixed by the current value
of the field. See also options.caseSensitive
.
Datasources should return a list of suggestions in the form of a Javascript array (in case of Ajax requests, the response should be a JSON body containing a single array).
For each suggestion in the array, the autocompleter needs a label (an HTML fragment to display in suggestion dropdown lists) and a value (a plain string to put into the text field when the suggestion is selected). So each suggestion may be either
this string will be used both as label and as value.
this object is supposed to have a label
property and a
value
property. Actually, these are the default names for
the properties; they can be changed in the constructor options.
The label
property may contain rich HTML, i.e. including
formatting tags.
The options to construct an autocompleter object are :
How many characters are needed before trying to find suggestions.
Name of the field that contains the HTML to display
(default is label
).
Name of the field that contains the value to put in input element
(default is value
).
Boolean value; toggles whether suggestions are displayed automatically
when available (true by default). If false, suggestions are only
displayed when the ARROW_DOWN
key is pressed.
How many milliseconds to wait after a keypress before displaying suggestions. Default is 200.
If true (the default), the current suggestion will be automatically inserted into the input element.
Maximum height for the suggestion DIV (in pixels). Default is 200.
Minimum width for the suggestion DIV (in pixels) Default is 200.
Offset (in pixels) from the left border of the input element to the left border of the suggestion DIV. Default is 0.
If this option is true and the user leaves the field with an illegal value (not in the suggestion list), the field is marked with a red background. Dfault is false.
If this option is defined and false, the field is marked with a red background when left with an empty value. Default is true.
If true, and if the datasource is a Javascript array, then that whole array is always displayed as suggestions, whatever may be typed in the input field (so the field behaves more or less like a SELECT). Default is false.
This option only applies if the datasource is a Javascript array
and if ignorePrefix
is false.
If true (the default), filtering of the datasource array
from the current value of the input field
will be case-sensitive.
Which color to put in the background when a "strict" field contains an illegal value (default is red).
How many items to skip when hitting the
PAGE_UP
or PAGE_DOWN
keys.
Default is 5
See the ChoiceList
documentation.
See the ChoiceList
documentation.
Classes that will be assigned at various stages to autocompleter DOM elements . Possible classes are
Class added to the input or textarea field while an Ajax
request is pending. Default is AC_loading
, a class that displays
an Ajax-loading icon.
Class for the dropdown div that displays the autocompletion choices.
Default is AC_dropdown
.
Class for displaying warning messages.
Default is AC_message
.
Returns an event handler to be bound to the onfocus
event on
an input field, i.e.
<input name="someInput" onfocus="myAutoCompleter.complete(this)">
The autocompleter will automatically register an
onblur
handler on the same field, so avoid
setting your own, which may cause unpredictable interactions.
However the autocompleter has its own event model with an
onLeave
event to which you can bind your handling code.
Detaches the autocomplete object from the input field
(i.e. remove onblur
and onkeypress
handlers
that were previously set by the autocomplete
method).
Displays the given message within a newly created dropdown DIV under the input field. Used internally to warn for example about illegal values.
For a general explanation on registering handlers for GvaScript events, see the event documentation. In short, you can register handlers either on the HTML input element, as in
<input name="someInput" onfocus = "myAutoCompleter.complete(this)" onBind = "bindHandler(this, event)" onLeave = "leaveHandler">
or on the javascript object, as in
myAutocompleter.onBind = function(event) { bindHandler(event.target, event) }; myAutocompleter.onLeave = leaveHandler;
Below is the list of events generated by autocompleter objects.
This event is triggered whenever the autocompleter object becomes associated with an input field; typically this occurs when the input field receives focus and then calls the /"autocomplete" method.
This event is triggered whenever the autocompleter object cuts the association with an input field; typically this occurs when the input field loses focus ( calls the /"autocomplete" method.
This event is triggered whenever the user has chosen
an item in the displayed suggestion list.
The event handler may use event.index
to know the index of the
selected choice.
This event is triggered when a choice in the dropdown list
of choices is highlighted.
The event handler may use event.index
to know the index of the
highlighted choice.
This event is triggered when the user presses the ESCAPE
key.