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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

{snippet:id=templateRelatedAttributes|javadoc=true|url=org.apache.struts2.components.UIBean}

Javascript-Related Attributes

{snippet:id=javascriptRelatedAttributes|javadoc=true|url=org.apache.struts2.components.UIBean}

Tooltip Related Attributes

{snippet:id=tooltipattributes|javadoc=true|url=org.apache.struts2.components.UIBean}

General Attributes

{snippet:id=generalAttributes|javadoc=true|url=org.apache.struts2.components.UIBean}

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">
    <@saf.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.

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

{snippet:id=tooltipdescription|javadoc=true|url=org.apache.struts2.components.UIBean}

{snippet:id=tooltipexample|lang=xml|javadoc=true|url=org.apache.struts2.components.UIBean}

Form Tag Reference

1. checkbox - renders a checkbox input field
2. checkboxlist - renders a list of checkboxes
3. combobox - renders a widget that fills a text box from a select
4. datepicker - renders a date selection widget using JavaScript and DOM
5. doubleselect - renders a double select widget, where the second drop down depends on the first
6. head - renders the HEAD section for specific themes, such as CSS and JavaScript imports
7. file - renders a file input field
8. form - renders an input form
9. hidden - renders a hidden form field
10. label - renders renders a label
11. optiontransferselect- renders an option transfer select component which is basically two select box with buttons in between allowing entries of each select to get transfer between each other.
12. optgroup - render an optgroup tag to be used within a select tag
13. password - renders a password textfield
14. radio - renders a radio button
15. reset - renders a reset form button
16. select - renders a select
17. submit - renders a submit button
18. textarea - renders a textarea
19. textfield - renders a textfield
20. timepicker - renders a timepicker
21. token - renders a hidden field to stop double-submission of containing forms
22. updownselect - renders a select component with buttons to move the elements in the select component up and down

Next: Non Form Tags