CSS Classes and Styles

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CSS Classes and Styles

CSS (Cascading Style Sheets) is a style sheet language used to describe the presentation of a (HTML) document. It is an important part of ZK to customize component's look and feel. If you are not familiar with CSS, please refer to CSS Tutorial.

There are a set of methods that could be used to set CSS styles for an individual component.

Notice that the DOM structures of many ZUL components are complicate, and CSS customization might depend on the DOM structure. For more information about how individual component is styled, please refer to ZK Style Guide.


Specifying the style is straightforward:

<textbox style="color: red; font-style: oblique;"/>

or, in Java:

Textbox tb = new Textbox();
tb.setStyle("color: red; font-style: oblique;");


In addition, you could specify the style class by use of HtmlBasedComponent.setSclass(String), such that you could apply the same CSS style to multiple components.

        .red {
            color: blue;
            font-style: oblique;
    <textbox sclass="red" /> <!-- first textbox -->
    <textbox sclass="red" /> <!-- another textbox -->

You could apply multiple style classes too. As shown below, just separate them with a space.

<textbox sclass="red error"/>


Like sclass, zclass is used to specify the CSS style class. However, zclass is the main CSS that each mold of each component has. If it is changed, all default CSS of the given component won't be applied. In other words, you have to provide a full set of CSS rules that a component's mold has.

Rule of thumb: specify zclass if you want to customize the look completely. Otherwise, use sclass to customize one or a few CSS styles.

For more information, please refer to ZK Style Guide.

content style and sclass

Some container components such as window, groupbox, detail have a content block, you have to use contentStyle to set its style.

For example,

<window title="below is content"  contentStyle="background:yellow">
    Hello, World!    

Scrollable Window

A typical use of contentStyle is to make a window scrollable as follows.

<window title="Scroll Example" width="150px" height="100px" contentStyle="overflow:auto" >
This is a long line to spread over several lines, and more content to display.
Finally, the scrollbar becomes visible.
This is another line.

Last Update : 2024/02/05

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