toloframework/man/xjs.view.md

# XJS
## View
In all this document, we will call __special object__ any object with an implicit attribute name.
That is any object with an attribute named __"0"__, like `{boolean init: true}` for instance.
Other objects, strings, numbers and so on are called __standard values__.

* [`focus`](xjs.view.focus.md): Bind the focus of an element to a linkableproperty.
* `innerhtml`: Bind a property to the innerHTML of an element.
* `textcontent`: Bind a property to the text content of an element.
* `value`: To use with INPUT, TEXTAREA, ...
* [`view.attribs`](xjs.view.view.attribs.md): Define linkable attributes of the view.
* `view.debug`: Boolean used to activate/deactivate the debug mode.
* `view.id`: .
* `view.init`: The function (defined in the code behind) to call just after construction.
* [`view.statics`](xjs.view.statics.md): Define static functions on the View.
* [`view.prototype`](xjs.view.prototype.md): Define member functions on the View.
* [`view.children`](xjs.view.view.children.md): Bind children of an element to an array or a list.
* `attrib.<names>`: .
* [`class.<names>`](xjs.view.class.md): Add a CSS class depending on the value of a bound boolean.
* [`class.*`](xjs.view.class.md): Add CSS classes depending on values of a bound booleans.
* [`event.<event-name>`](xjs.view.event.md): Adding events and gestures handlers.
* [`on.<attrib-name>`](xjs.view.on.md): Call a function from code behind as soon as the attribute's value changed.
* `style.<name>`: .
* [`{Bind ...}`](xjs.view.bind.md): .
* `{Intl ...}`: Get internaTionalisazion string.

### Code behind
Even if XJS.View has been made as powerful as possible, there are still cases where Javascript code is needed.
Here is a dummy example to show you how to use code behind. The view will add a new line when its `value` attribute will be set.

__foobar.js__
```js
var CODE_BEHIND = {
  onValueChanged: function( value ) { this.$.appendChild( document.createTextNode( value + "\n" ) ); }
};
```

__foobar.xjs__
```
{View PRE
  view.attribs: {
    value: {string behind: onValueChanged }
  }}
```


### Defining HTML elements
```
{TEXTAREA cols: 80 rows: 5 "Hello world!"}
```

```
{UL [
  {LI [{B First} ": Arthur."}]}
  {LI [{B Second} ": Bonjovi."}]}
]}
```

* `"0"`: The element name must be uppercase.
* `"1"`: The children cvan be of three types:
    * __array__: array of elements to add.
    * __string__: textContent.
    * __binding__: content is binded to a linkable property.
* Named attributes are directly mapped to the HTML element attributes.

#### Events

#### CSS Classes manipulation
You can set CSS classes in a static way:
```
{DIV class: "elevation-8 round"}
```
or in a bounded way:
```
{DIV class: {Bind style}}
```

You can also bind the existence of a given class to a boolean property:
```
// Add class `elevation-8` if and only if `pressed === true`.
{DIV class.elevation-8: {Bind pressed}}
```
```
// Add class `highlight` if and only if `pressed === false`.
{DIV class.|highlight: {Bind pressed}}
```
```
// If `pressed === true`, add class `elevation-8`, otherwise add class 'elevation-2'.
{DIV class.elevation-8|elevation-2: {Bind pressed}}
```

And if you need a more complex logic to set classes, you can use code behind:
```
// As soon as `flat` or `pressed` has changed, call teh code behind function
// `computeClass()` to return an array of classes to set.
{DIV class.*: {Bind [flat, pressed] computeClasses}}
```

It is possible to define a list of functions:
```
{DIV class.*: [
  {Bind [flat, pressed] computeClassesWhenPressed}
  {Bind [flat, enabled] computeClassesWhenEnabled}
]}
```