ZK Component Reference/Essential Components/Script

Script

• Demonstration: Script
• Java API: Script
• JavaScript API: Script
• Style Guide: N/A

Employment/Purpose

The script component is used to specify the script codes running at the browser. Notice that, unlike zscript, the script codes are running at the browser. They are usually written in JavaScript which is supported by the most of browsers. The simplest format is as follows.

Example

<window id="win">
	<button label="change color" onClick='Clients.evalJavaScript("myfunc()")' />
</window>
<script type="text/javascript">
	function myfunc() {
	    jq("$win").css("backgroundColor", "blue");
	}
 </script>

Defer the Evaluation

By default, the specified JavaScript code will be evaluated as soon as the page is loaded. By specifying defer="true", the JavaScript code won't be evaluated until all ZK widgets are created and bound to the DOM tree.

<textbox id="inp"/>
<script defer="true">
   this.$f("inp").setValue("initialized");
</script>

The defer attribute can be used with a JavaScript file as shown below. Then, the JavaScript file will be loaded after all widgets are created and bound to the DOM tree.

<script src="/js/foo.js" defer="true"/>

This is required if the script to load intends to manipulate a ZK widget's DOM elements. defer="true" can ensure that all widgets' DOM elements are already generated.

Alternatives

script directive

Instead of using the script component, you could use the script directive instead. It does not support defer, but it is more efficient since no component is created.

<?script src="~./js/zk.debug.wpd"?>
<?script content="jq.IE6_ALPHAFIX='.png';"?>

where the first statement loads the debug utility and the second generates a JavaScript code snippet directly.

HTML script tag

Another alternative is the HTML SCRIPT tag. For example, we could define global variables and functions as follows

<n:script xmlns:n="native"><!-- use the native namespace -->
	var a_global_variable;
	function a_global_function () {
		alert("native script");
	}
	alert("you can not access this as widget but evaluated immediately");
</n:script>

Supported Events

Name	Event Type
None	None

• Inherited Supported Events: AbstractComponent

Supported Children

*NONE

Use Cases

Version	Description	Example Location
5.0	Overview and Tutorial	Client Side Programming ZK Client-side Reference: General Control