Alien::GvaScript::Form - Wrapper around HTML Forms
<form id="my_form" onsubmit="return false;"> <div repeat="foo"> <h2>Foo #{foo.count}</h2> <input type="text" name="person.name"/> <input type="text" name="person.bdate"/> This is the repeated foo section <table> <tr repeat="bar"> <td>Item #{bar.count}</td> <td><input name="#{bar.path}.buz"></td> <td><button onclick="GvaScript.Form.remove('#{bar.path}')"> Remove this row </button></td> </tr> </table> <button onclick="GvaScript.Form.add('#{foo.path}.bar')"> Add a bar </button> </div> <button onclick="GvaScript.Form.add('foo')">Add a foo</button> </form> <script> var gvascript_form = new GvaScript.Form('my_form', { datatree: {name:'kitty', bdate:'01.01.1990'}, dataprefix: 'person', // 'active' form elements registry: [ ['input', 'mouseover', function(event) {}], ['input', 'mouseout', function(event) {}], ['input', 'change', function(event, newv ,oldv) {}], ['input', 'init', function(event, newv) {}] ], // handlers to form's custom events onInit: function(gva_form) {}, onRepeatBlockRemove: function(gva_form, arg) { arg[0] // removed repeat name arg[1] // removed repeat path }, onRepeatBlockAdd: function(gva_form, arg) { arg[0] // added repeat name arg[1] // added repeat path }, onChange: function(gva_form, event) { // event.target -> element changed // event.memo.oldvalue -> changed element's old value // event.memo.newvalue -> changed element's new value }, onSubmit: function(gva_form) { // .... // do form submission // .... if(success) {gva_form.fire('AfterSubmit', arg)} else if(data_validation_error) {gva_form.fire('DataValidationError', arg)} else {gva_form.fire('SubmitFailure', arg)} }, onAfterSubmit: function(gva_form, arg) {}, onDataValidationError: function(gva_form, arg) {}, onSubmitFailure: function(gva_form, arg) {}, onBeforeDestroy: function(gva_form, arg) {} } </script>
This module of Alien::GvaScript manages forms with hierarchical fields and dynamically repeated sections. It works in close collaboration with Alien::GvaScript::Repeat.
The design is partially inspired by the Web Forms 2.0 proposal (http://www.whatwg.org/specs/web-forms/current-work/), but is not an attempt to implement the proposed specification: there are some differences both in syntax and in semantics.
Web Forms 2.0
new GvaScript.Form(form_id[, options])
id of the HTML form to extend
hash of optional properties that would define the behavior of the form
tree represention of the initial form data.
Ex:
{ name: 'barbie', age: '49', friends: [ { name: 'ken', age: '35' }, { name: 'jen', age: '55' } ] }
sometimes it's helpful to prefix the html input names to give them 'context'.
Ex: doll.name doll.friends.0.name.
doll.name
doll.friends.0.name
in this example, the dataprefix should be set to 'doll'
a list of arrays [expression, eventName, handler].
[expression, eventName, handler]
each item in the array would be passed over to the "notify" method.
function to be called after the successful initialization of the GvaScript.Form instance.
function to be called after a block in a repeated section is removed
Signature
function onRepeatBlockRemove(gva_form, arg) { // gva_form : GvaScript.Form instance // arg: array containing repeat name as first element and repeat path as second }
function to be called after a block in a repeated section is added
function onRepeatBlockAdd(gva_form, arg) { // gva_form : GvaScript.Form instance // arg: array containing repeat name as first element and repeat path as second }
function to be called when any of the form's elements has changed or onAdd/onRemove of a repeatable section.
function onChange(gva_form, event) { // gva_form : GvaScript.Form instance // event: Event object fired by the change on the form element // Has a memo object that has olvalue and newvalue set unless // called from the Repeat module }
function to be called directly before the form submits.
function onBeforeSubmit(gva_form) { // gva_form : GvaScript.Form instance // return false if you want to stop the form from submitting }
function to be called when the form is submit.
function onSubmit(gva_form) { // gva_form : GvaScript.Form instance // use to fire 'onAfterSubmit', 'onSubmitFailure' or 'onDataValidationError' }
function to be called right before the form instance calls the destroy method.
Callback useful for doing some inhouse cleaning before the form gets removed from the DOM.
Event handlers for custom form events. The form instance should fire these events so as corresponding handler can be fired.
initializes and instance of Alien::GvaScript::ActionsBar.
actionsbar : { container : 'container_id', actions : [ { label : 'Submit Form', type : 'submit' }, { label : 'Init Form', type : 'button', callback : function() { // 'this' correspond to the button GvaScript.Form.init('form', datatree); } } ] }
Repeat elements may occur outside of forms and therefore are described in a separate document; see Alien::GvaScript::Repeat.
The "init" method inspects all form elements for an autofocus attribute; the first element that possesses this attribute automatically receives focus.
autofocus
Similarly, when a repetition block is added into the form through the "add" method, the first element within that repetition block that possesses an autofocus attribute automatically receives focus.
gvascript_form.destroy()
instance destructor - will unregister the GvaScript.Form instance from the GvaScript.Forms namespace and will remove all of its observers.
gvascript_form.getId()
returns the id of the form element that the gvascript_form instance is wrapped around.
gvascript_form.fire(eventName[, arg])
used to fire event on the for instance and thus called corresponding responders and instance callback.
eventName: eventName to fire without the 'on' prefix.
eventName
arg argument to send over to the corresponding responder(s) and callback.
arg
this method will
execute the early responders set the on[eventName]
execute instance on[eventName] callback
execute the responders set the on[eventName]
execution sequence will stop whenever one of the responders or callback returns false
false
NOTE that the onBeforeSubmit, onSubmit events cannot be notified programatically. You actually need to call form.submit() for these events to be fired.
gvascript_form.register(expression, eventName, handler) GvaScript.Form.register(form, expression, eventName, handler)
tells the form to watch the eventName on elements that match the expression and to fire the corresponding handler.
expression (String) - A css selector
expression
eventName (String) - The name of the event, in all lower case, without the "on" prefix e.g., "click" (not "onclick").
A custom "init" event is also supported which is fired on an input that gets its value initialized with the initialization of the form.
handler (Function) - handler to fire.
handler
function handler(event[, newValue[, oldValue]]) { event.target // element being observed }
newValue is set for the change and the init events.
newValue
change
init
oldValue is set for the change.
oldValue
NOTE: Form.Element.setValue method is wrapped in GvaScript.ProtoExtensions module to programatically fire the blur event after setting the value on the input, and hence firing the change handler if any.
[This method can be called either as an instance method or as a generic method. If calling as a generic, pass the form HTMLElement/id in as the first argument.]
gvascript_form.unregister(expression[, eventName[, handler]]) GvaScript.Form.unregister(form, expression[, eventName[, handler]])
removes observers set on given expression. if eventName is provided, will only stop observing that eventName. if handler is also provided, will just stop calling this handler.
NOTE that the same handler signature should be used in the register method for it to work in the unregister method.
gvascript_form.init(initial_tree, prefix) GvaScript.Form.init(form, initial_tree, prefix)
form is the id of a form (or directly the DOM element). Optional initial_tree is a javascript nested datastructure containing initial values for fields, that will be passed to the "fill_from_tree" method.
form
initial_tree
var flat_hash = GvaScript.Form.to_hash(form);
Inspects the contents of all fields in form and returns a flat hash of pairs (key-value).
var tree = GvaScript.Form.to_tree(form);
Inspects the contents of all fields in form and returns a data tree, were dotted names in form names are expanded into sub-arrays or sub-hashes. So for example if the form looks like
<input name="father.firstname"> <input name="father.lastname"><br> <input name="mother.firstname"> <input name="mother.lastname"><br> <div repeat="child" repeat-start="1"> <input name="#{child.path}.firstname"><br> </div>
and if that form has been expanded with 3 repetition blocks for children, the resulting tree would be
{ "father" : {"firstname" : ..., "lastname": ...}, "mother" : {"firstname" : ..., "lastname": ...}, "child" : [ {"firstname": ...}, {"firstname": ...}, {"firstname": ...} ] }
GvaScript.Form.fill_from_tree(form, field_prefix, tree);
Fills the form from values found in tree (this is the reverse of the "to_tree" operation). Optional field_prefix is prepended to key names in tree for finding the corresponding form fields.
tree
field_prefix
The method walks through nested subtrees in tree: the sequence of keys leading to a leaf is concatenated into a flat string, with dot separators, and if the form has a corresponding input element, the value of that element is set to the value of the leaf. Furthermore, if the initial tree contains repeated data sets (array subtrees), and if the form contains repeat elements with the same path, then new repetition blocks are dynamically created to match the number of items in the array: so if the form above is filled with the following tree
{ "child" : [ {"firstname": "Abel"}, {"firstname": "Bob"}, {"firstname": "Cod"}, {"firstname": "Dave"}, ] }
then four repetition blocks will automatically created in the form.
GvaScript.Form.add(repeat_name, count);
Creates one or several new repetition blocks. The parameter count is optional and defaults to 1. Focus is automatically given to the first input element in the last repetition block that has an autofocus attribute (if any).
count
See "add" in Alien::GvaScript::Repeat for more explanations on the add operation.
add
GvaScript.Form.remove(repeat_block[, live_update]);
Removes a repetition block from the DOM. The argument is either a DOM element or a string containing the element id.
param Boolean live_update: flag to indicate whether the 'remaining' repeatable sections are to be also removed from DOM, recreated by re-merging the data with repeat template, then finally re-appended to the DOM. Default true.
Boolean
All repetition blocks above the removed block are renumbered, leaving no hole in the index sequence. To do so, these blocks are also removed from the DOM, and then added again through the "add" method. This operation is implemented by "remove" in Alien::GvaScript::Repeat.
The recreated blocks are then re-populated with their previous input values.
GvaScript.Form.autofocus(element);
Inspects DOM children of element, and gives focus to the first child that has an autofocus attribute.
element
namespace that holds all active instances of GvaScript.Form
instances are unique per form id
GvaScript.Forms.get(id)
finds and returns the GvaScript.Form instance where id is the unique id of the form HTMLElement.
A repository of global listeners notified about every step of the GvaSript.Form lifecycle.
Sometimes, you need to provide generic behaviors over all GvaScript.Form(s) in a single application.
To achieve this, GvaScript.Form provides global Responders that will be executed for every GvaScript.Form instance.
Responders by default are executed after the instance specific event callback.
GvaScript.Form.Responders.register({eventName: handler}[, {eventName: handler}[, ...]]})
adding one or more global form events responders.
Supported eventNames: onInit, onChange, onBeforeSubmit, onSubmit, on[XXX] where on[XXX] is a custom event name.
onInit, onChange, onBeforeSubmit, onSubmit, on[XXX]
on[XXX]
GvaScript.Form.Responders.unregister({eventName: handler}[, {eventName: handler}[, ...]]})
unregistering one or more global form events responders.
Identical to GvaScript.Form.Responders except that these responders would be executed before the instance specific callback.
To install Alien::GvaScript, copy and paste the appropriate command in to your terminal.
cpanm
cpanm Alien::GvaScript
CPAN shell
perl -MCPAN -e shell install Alien::GvaScript
For more information on module installation, please visit the detailed CPAN module installation guide.