It defines a set of variables. It is equivalent to the setVariable method of Component, if it has a parent component, and Page, if it is declared at the page level.
As depicted below, variables is convenient to assign variables without programming.
<window>
<variables rich="simple" simple="intuitive"/>
</window>
It is equivalent to
<window>
<zscript>
self.setVariable("rich", "simple", false);
self.setVariable("simple", "intuitive", false);
</zscript>
</window>
Of course, you can specify EL expressions for the values.
<window>
<window id="w" title="Test">
<variables title="${w.title}"/> 
1: ${title}
</window>
2: ${title}
</window>
Like Component's setVariable, you can control whether to declare variables local to the current ID space as follows. If not specified, local="false" is assumed.
<variables simple="rich" local="true"/>
By default, the value is assigned to the variable directly after evaluating EL expressions, if any. For example, "apple, ${more}" is evaluated to "apple, orange", if more is "orange", and assigned to the variable.
If you want to specify a list of values, you can specify the composite attribute with list as follows.
<variables simple="apple, ${more}" composite="list"/>
Then, it is converted to a list with two elements. The first element is "apple" and the second "orange".
If you want to specify a map of values, you can specify the composite attribute with map as follows.
<variables simple="juice=apple, flavor=${more}" composite="map"/>
Then, it is converted to a map with two entries. The first entry is ("juice", "apple") and the second ("flavor", "orange").
In the following example, var is an empty string.
<variables var=""/>
To define a variable with the null value, use the following statement.
<variables var="${null}"/>
To assign a variable with a reserved name, say, forEach, you have to specify a namespace (which can be anything but ZK namespace) as follows.
<variables m:forEach="a value" xmlns:m="http://whatever.com"/>
Then, forEach will be considered as a variable rather than the iterative condition.