Actions and Effects

Since 5.0.6

The client-side action is used to control how to perform an action at the client. Typical use is to control the effect of showing or hiding a widget. For example, with client-side action, you could use the so-called slide-down effect to display a widget.

It is a generic feature available to HtmlBasedComponent, so you could apply it to almost all widgets.

The client-side action allows the developer to control some actions without JavaScript. If you want to have full control (and are OK to write some JavaScript code), please refer to ZK Client-side Reference for complete control of the client-side behavior.

How to Apply Client-side Actions

To apply the client-side action to a widget, you have to assign a value to the action property (HtmlBasedComponent.setAction(String)). The syntax is as follows.

action="action-name1: effect1; action-name2: effect2"

The action name (e.g., action1) has to be one of the predefined names, such as show and hide. The action effect (e.g., effect1) has to be one of the predefined effects, such as slideDown and slideUp.

For example, we could use the slide-down effect to display a window as follows.

<zk>
	<button label="Show a modal window" onClick="wnd.doModal()"/>
	<window id="wnd" title="Modal" border="normal" width="300px"
	 action="show: slideDown" visible="false">
		This is a modal window.
	</window>
</zk>

In addition, you could specify additional options by enclosing them with the parentheses as follows.

<div action="show: slideDown({duration: 1000}); hide: slideUp({duration: 300})">
....
</div>

which specifies the duration of sliding down is 100 milliseconds, and the duration of sliding up is 300 milliseconds.

Security Note: the options is actually a JavaScript object (i.e., a map, Map), and ZK passes whatever is being specified to the client for evaluation. Thus, if you allow the user to specify the effect, you shall encode it first to avoid cross-site scripting.

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Predefined Actions

Here is a list of predefined actions.

Name	Description
show	The show action is used to display a widget (making a widget visible). When a visible widget is attached to a page, the show action will take place too.
hide	The hide action is used to hide a widget (making a widget invisible). When a visible widget is detached from a page, the hide action will take place too.
invalidate	The invalidate action is invoked when a visible widget is invalidated, i.e., when Component.invalidate() is called. Example, action="invalidate: slideDown".

Predefined Effects

Here is a list of predefined effects.

Name	Description
slideDown	Slides down to display this widget (making a widget visible).
slideUp	Slides up to hide this widget (making a widget invisible).
slideIn	Slides in to display this widget (making a widget visible).
slideOut	Slides out to hide this widget (making a widget invisible).

Predefined Options for Effects

Option Name	Acceptable Values	Description
anchor	t, b, l, r	The 4 values represent the direction to slide: top to bottom , bottom to top, left to right, right to left respectively.
duration	a number of milliseconds	The time to slide up/down/in/out a widget. The larger the time, the slower the widget slides.

Custom Actions

If you want to take some actions other than the predefined actions listed above, you have to override the corresponding method at the client. For example, suppose you'd like to change the color when a label's value (Label.setValue(String)) is changed. Then, you could do as follows:

<label id="inf2">
	<attribute w:name="setValue">
	function (value, fromServer) {
		this.$setValue(value, fromServer);
		if (this.desktop) {
			this._red = !this._red;
			this.setStyle('background:'+(this._red ? 'red':'green'));
		}
	}
	</attribute>
</label>

For more information, please refer to ZK Client-side Reference: Widget Customization.

Custom Effects

For adding your custom effects, please refer to ZK Client-side Reference: Customization: Actions and Effects for details.

Notes for Upgrading from ZK 3

They are both called Client-side Actions, but they are different and you have to rewrite them to make them work under ZK 5:

1. The action names were changed and the support is limited to show and hide (while ZK 3 supports any onxxx).
2. The action operation must be the name of one of the methods defined in Actions (while ZK 3 is the JavaScript code).
3. It is part of HtmlBasedComponent (while ZK 3 is XulElement).