Within the form tags, there are two classes of tags: the form tag itself, and all other tags, which make up the individual form elements. The behavior of the form tag is different than the elements enclosed within it.

Form Tag Themes

As explained in Themes and Templates, the HTML Tags (which includes Form Tags) are all driven by templates. Templates are grouped together to create themes. The framework bundles three themes in the distribution.

The predefined themes can be used "as is" or customized.

Simple theme caveats

The downside of using the simple theme is that it doesn't support as many of the attributes that the other themes do. For example, the label attribute does nothing in the simple theme, and the automatic display of error messages is not supported.

Common Attributes

All the form tags extend the UIBean class. This base class provides a set of common attributes, that can be grouped in to three categories: templated-related, javascript-related, and general attributes. The individual attributes are documented on each tag's reference page.

In addition to the common attributes, a special attribute exists for all form element tags: form (${parameters.form}). The form property represents the attributes used to render the form tag, such as the form's id. In a template, the form's ID can be found by calling ${parameters.form.id}.

Template-Related Attributes

Javascript-Related Attributes

Tooltip Related Attributes

General Attributes

Value/Name Relationship

In many of the tags (except for the form tag) there is a unique relationship between the name and value attributes. The name attribute provides the name for the tag, which in turn is used as the control attribute when the form is submitted. The value submitted is bound to the name. In most cases, the name maps to a simple JavaBean property, such as "postalCode". On a submit, the value would be set to the property by calling the setPostalCode mutator.

Likewise, a form control could be populated by calling a JavaBean accessor, like getPostalCode. In the expression language, we can refer to the JavaBean property by name. An expression like "%{postalCode}" would in turn call getPostalCode.

<@s.form action="updateAddress">
    <@s.textfield label="Postal Code" name="postalCode" value="%{postalCode}"/>
    ...
</@s.form>

However, since the tags imply a relationship between the name and value, the value attribute is optional. If a value is not specified, by default, the JavaBean accessor is used instead.

<@s.form action="updateAddress">
    <@s.textfield label="Postal Code" name="postalCode"/>
    ...
</@s.form>

While most attributes are exposed to the underlying templates as the same key as the attribute (${parameters.label}), the value attribute is not. Instead, it can be accessed via the nameValue key (${parameters.nameValue}). The nameValue key indicates that the value may have been generated from the name attribute rather than explicitly defined in the value attribute.

ID Name Assignment

All form tags automatically assign an ID to the control, but the ID can be overridden if needed.

Form labelposition propagation

When labelposition attribute was defined for <s:form> tag it will be propagated to all form elements, but if form element defines its own labelposition it will take precedence over <s:form>'s attribute. Since 2.3.17.

Required Attribute

The required attribute on many UI tags defaults to true only if you have client-side validation enabled, and a validator is associated with that particular field.

Tooltip

tooltipConfig is deprecated, use individual tooltip configuration attributes instead

Every Form UI component (in xhtml / css_xhtml or any other that extends them) can have tooltips assigned to them. The Form component's tooltip related attribute, once defined, will be applied to all form UI components that are created under it unless explicitly overridden by having the Form UI component itself defined with their own tooltip attribute.

In Example 1, the textfield will inherit the tooltipDelay and tooltipIconPath attribute from its containing form. In other words, although it doesn't define a tooltipIconPath attribute, it will have that attribute inherited from its containing form.

In Example 2, the textfield will inherit both the tooltipDelay and tooltipIconPath attribute from its containing form, but the tooltipDelay attribute is overridden at the textfield itself. Hence, the textfield actually will have its tooltipIcon defined as /myImages/myIcon.gif, inherited from its containing form, and tooltipDelay defined as 5000.

Example 3, 4 and 5 show different ways of setting the tooltip configuration attribute.
Example 3: Set tooltip config through the body of the param tag
Example 4: Set tooltip config through the value attribute of the param tag
Example 5: Set tooltip config through the tooltip attributes of the component tag

Next: UI Tag Reference