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A header for a Groupbox, Window, and Panel. It may contain either a text label, using LabelElement.setLabel(String), or child elements for a more complex caption.

Preload Image

Since  6.0.0

The feature is applied to all of the LabelImageElement and Image components.

By default the preload function is disabled, so users have to specify the custom-attributes and set it to true. For example,

<caption image="xxx.png" label="caption">
  <custom-attributes org.zkoss.zul.image.preload=”true”/>

Or specify it just below the root component.

For example,

  <custom-attributes org.zkoss.zul.image.preload=”true”/>
  <caption image="xxx.png" label="caption">
  <image src="xxx.png"/>

As you can see, the custom-attributes will be checked recursively.


ZKComRef Caption Example.png

     <window border="normal" width="350px">
          <caption label="This is a caption"/>
             <groupbox width="300px">
                  <caption label="fruits"/>
                  <radiogroup onCheck="fruit.value = self.selectedItem.label">
                     <radio label="Apple"/>
                  <radio label="Orange"/>
                  <radio label="Banana"/>  

Supported Events

Event Type
None None

Supported Children


Use Cases

Version Description Example Location
5.0 How to use the title and caption inside a Window Title and Caption

Version History

Last Update : 2022/07/08

Version Date Content

Last Update : 2022/07/08

Copyright © Potix Corporation. This article is licensed under GNU Free Documentation License.