ZK Component Reference/Essential Components/A

A

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

Employment/Purpose

The same as HTML A tag.

Properties

Autodisable

A.setAutodisable(String) is used to disable an anchor automatically, when it is clicked. It is useful to prevent the user from clicking it twice (and firing redundant requests), which is common if the request takes long to serve.

The simplest use is to specify it with self as follows. Then, the anchor is disabled when it is clicked.

<a id="ok" label="OK" autodisable="self" />

If you'd like to disable several anchors, you could specify all of them in this property by separating with a comma. For example, the following disables both anchors, when one of them is clicked.

<a id="ok" label="OK" autodisable="ok,cancel" />
<a id="cancel" label="Cancel" autodisable="ok,cancel" />

The anchor will be enabled automatically, after the request has been served (i.e., the response has been sent back to the client). If you prefer to enable them manually (i.e., by calling A.setDisabled(boolean) explicitly), you could prefix the ID with a plus (+). For example,

<a id="ok" label="OK" autodisable="+self, +cancel" />

Then, you could enable them manually under the situation depending on your application's requirement, such as

if (something_happens) {
   ok.setDisabled(false);
   cancel.setDisabled(false);
}

Enable Autodisable for All Anchors

As described in ZK Developer's Reference: Customization, you could customize ZK to enable autodisable for all anchors by specifying the following in the custom language addon:

<language-addon>
    <language-name>xul/html</language-name>
    <component>
        <component-name>a</component-name>
        <extends>a</extends>
        <property>
            <property-name>autodisable</property-name>
            <property-value>self</property-value>
        </property>
    </component>
</language-addon>

File Download Link

When a user clicks <a/> whose target is _self (default value) will cause a browser to trigger the event onbeforeunload, then ZK depends on this event to remove a desktop. This also apply to browser-processed links. Links that do not open a page, but provide a browser instruction to open a different service, such as mailto:, tel:, etc.

Hence, after clicking the hyperlink, all ZK client ajax doesn't work anymore. Here are several correct ways to create a file download link:

open a new tab

specify _blank and your browser will produce a new tab and close immediately.

<a href="report.pdf" target='_blank'>download</a>

After clicking a link like <a href="report.pdf" target='_self'>download</a>, you will find ZK doesn't send AJAX requests anymore to the server.

download attribute

A browser will prompt the user to save the linked URL instead of navigating to it.

<zk xmlns:c="client/attribute">
<a href="report.xls" c:download="" target='_self'>download</a>
</zk>

Please refer to download attribute

Example

<a href="http://www.zkoss.org" label="Visit ZK!"/>

In addition, you could add child components to A too:

<a href="http://www.zkoss.org" label="Visit ZK!" image="zk.png">
  <grid>
    <rows>
      <row>What ever content</row>
    </rows>
  </grid>
</a>

Notice that a child component might also handle the mouse click, so the final result of clicking on a child component is really up to which child component is used.

The href attribute can be an URI. For example,

<a href="/foo" label="Foo" />
<a href="goo" label="Goo" />

If the URI starts with "/", ZK will encode it with the application's context path. Otherwise the path is relative to the path given by Desktop.getDirectory().

Supported Events

Name	Event Type
None	None

• Inherited Supported Events: LabelImageElement

Supported Children

*ALL

Use Cases

Version	Description	Example Location

Version History

Version	Date	Content
5.0.5	October, 2010	A supports any children.
7.0.2	May, 2014	Support autodisable property for A component