@data-content : The Dynamic Content Attribute

The data-content attribute provides a mechanism for dynamically generating and inserting content into elements during the data binding phase.

This is supported by the data-content-type and data-content-action attributes.

On this page

Usage
- Basic Syntax
- Content Actions
Supported Elements
Binding Values
Notes
Examples
See Also

Usage

The data-content attribute accepts a string value containing HTML/XHTML markup or plain text. The content is parsed according to the document’s default parser or the MIME type specified in data-content-type. Unlike static content declared in the template, data-content evaluates at runtime, allowing you to:

Generate content from bound data values
Insert dynamically constructed HTML/XHTML markup
Replace element content conditionally
Prepend or append dynamic content to existing elements
Create inline templates without nested element structures

This attribute is particularly useful when:

Content structure varies based on data
You need to generate markup programmatically
Template content comes from external sources
You want to avoid deeply nested template structures

Basic Syntax

<!-- Simple text content -->
<label data-content="{{model.userName}}">Default Name</label>

<!-- HTML markup content -->
<div data-content="<p>Hello <strong>{{model.name}}</strong></p>"></div>

<!-- Dynamic content from bound expression -->
<span data-content="{{model.dynamicContent}}"></span>

<!-- Dynamic content in a template to be used when looping over each item (completely dynamic) -->
<template data-bind="{{context.items}}" data-content="{{model.layout}}" data-content-type="text/html" ></template>

Content Actions

The data-content-action attribute controls how the content is inserted:

Action	Behavior	Default
`append`	Add after existing content	No (except for VisualComponent)
`prepend`	Add before existing content	No
`replace`	Replace all existing content	Yes (for most components)

<!-- Replace existing content (default for labels) -->
<label data-content="{{model.newText}}">Old text</label>

<!-- Append to existing content -->
<div data-content="<p>{{model.additionalInfo}}</p>" data-content-action="append">
    <p>Existing content stays here</p>
</div>

Supported Elements

The data-content attribute is supported on the following elements:

Primary Support

<label> - Text labels with dynamic content (HTMLLabel)
<template> - Template elements with inline content definition (HTMLTemplate)
<frame> - Frame elements for document assembly (HTMLFrame)

General Support

All VisualComponent descendants - Any visual element that inherits from VisualComponent

Implementation Details

HTMLLabel: Content is set directly and rendered as text literal during pre-layout phase.

HTMLTemplate: Content is parsed as a template and used instead of child elements.

HTMLFrame: Content is parsed as HTML document and used for frame content.

VisualComponent: Content is parsed according to MIME type and inserted per the specified action.

Binding Values

Expression Evaluation

The data-content attribute value is evaluated during data binding, supporting:

<!-- Direct property binding -->
<label data-content="{{model.userName}}"></label>

<!-- Legacy syntax -->
<label data-content="{@:model.userName}"></label>

<!-- String concatenation -->
<label data-content="{{concat('Hello ', model.name)}}"></label>

<!-- Conditional content -->
<label data-content="{{model.isActive ? 'Active' : 'Inactive'}}"></label>

Content Type Specification

Use data-content-type to specify the MIME type of the content:

<!-- HTML content (default) -->
<div data-content="<p>HTML content</p>" data-content-type="text/html"></div>

<!-- XHTML content -->
<div data-content="<div xmlns='http://www.w3.org/1999/xhtml'><p>XHTML</p></div>"
     data-content-type="application/xhtml+xml"></div>

<!-- Plain text -->
<div data-content="{{model.plainText}}" data-content-type="text/plain"></div>

Markup Requirements

Content must be well-formed according to the specified type:

For HTML/XHTML:

Must be valid markup
Elements must be properly closed
Attributes must be quoted
Namespace declarations required for XHTML

For Plain Text:

No parsing applied
Rendered as literal text
Special characters handled automatically

Notes

Content Parsing

Parse Timing: Content is parsed and inserted during the data binding phase, after all binding expressions are evaluated.
Parser Selection: The document’s parser for the specified MIME type is used. If no type is specified, the default content MIME type is used.
Validation: In strict conformance mode, parse errors will throw exceptions. In lax mode, warnings are logged.
Component Requirements: Parsed content must result in compatible components for the target element.

Label-Specific Behavior

For <label> elements:

Content is set as simple text during pre-layout
Existing content is cleared
No HTML parsing occurs
Most efficient for simple text replacement
Always replaces existing content

Template-Specific Behavior

For <template> elements:

Content defines the template to repeat
Takes precedence over child elements
Must contain valid HTML/XHTML
Creates parsable template generator
Useful for dynamic template definition

Frame-Specific Behavior

For <frame> elements:

Content must be a complete HTML document
Parsed as HTMLDocument component
Used for document assembly scenarios
Initialized and data-bound after parsing
Only accepts full XHTML documents

Content Action Behavior

The default data-content-action varies by component:

Label: Always replaces (action ignored)
Template: Always replaces (action ignored)
Frame: Always replaces (action ignored)
VisualComponent: Default is append

Performance Considerations

Parsing content has overhead; cache when possible
Use data-style-identifier with repeated patterns
Avoid complex markup in large iterations
Consider building content in code for complex scenarios
Pre-process and simplify content when feasible

Security Considerations

Content is parsed and executed in the document context
Validate external content sources
Sanitize user-provided content
Be cautious with dynamic code generation
Use strict conformance mode for validation

Examples

1. Simple Text Replacement in Label

Replace label text with bound data:

<!-- Model: { userName: "John Smith" } -->
<label data-content="{{model.userName}}">Loading...</label>

<!-- Result: John Smith -->

2. Dynamic Formatted Text

Generate formatted content from data:

<!-- Model: { firstName: "Jane", lastName: "Doe", title: "Dr." } -->
<label data-content="{{concat(model.title, ' ', model.firstName, ' ', model.lastName)}}">
    Name Placeholder
</label>

<!-- Result: Dr. Jane Doe -->

3. Conditional Content Display

Show different content based on conditions:

<!-- Model: { isActive: true, status: "Premium" } -->
<label data-content="{{model.isActive ? concat('Active - ', model.status) : 'Inactive'}}">
    Status Unknown
</label>

<!-- Result: Active - Premium -->

4. Dynamic HTML Content in Div

Insert formatted HTML markup:

<!-- Model: { productName: "Widget Pro", price: 29.99, inStock: true } -->
<div data-content="<div><strong>{{model.productName}}</strong><br/>Price: ${{model.price}}<br/><em>{{model.inStock ? 'In Stock' : 'Out of Stock'}}</em></div>"></div>

<!-- Renders formatted product info -->

5. Inline Template Content

Define template content inline without nested elements:

<!-- Model: { items: [{name: "A"}, {name: "B"}] } -->
<template data-bind="{{model.items}}"
          data-content="<div style='padding:5pt; border:1pt solid #ccc;'>{{.name}}</div>">
</template>

<!-- Generates: -->
<!-- <div>A</div> -->
<!-- <div>B</div> -->

6. Appending Dynamic Content

Add content after existing elements:

<div data-content="<p><em>{{model.disclaimer}}</em></p>" data-content-action="append">
    <p>Main content appears here first.</p>
</div>

<!-- Results in main content followed by disclaimer -->

7. Prepending Header Content

Add content before existing elements:

<div data-content="<h2>{{model.title}}</h2>" data-content-action="prepend">
    <p>This paragraph will appear after the title.</p>
</div>

<!-- Results in title followed by paragraph -->

8. Complex Multi-Line HTML Content

Generate complex markup structure:

<!-- Model: { user: {name: "Alice", role: "Admin", department: "IT"} } -->
<div data-content="<div style='border: 2pt solid #336699; padding: 10pt;'>
    <h3 style='margin: 0; color: #336699;'>{{model.user.name}}</h3>
    <div style='margin-top: 5pt;'>
        <strong>Role:</strong> {{model.user.role}}<br/>
        <strong>Department:</strong> {{model.user.department}}
    </div>
</div>">
</div>

9. Dynamic Table Content Generation

Create table structure dynamically:

<!-- Model: { columns: ["ID", "Name", "Status"], hasData: true } -->
<div data-content="<table style='width:100%;'>
    <thead>
        <tr>
            <template data-bind='{{model.columns}}'>
                <th>{{.}}</th>
            </template>
        </tr>
    </thead>
    <tbody>
        <tr><td colspan='3' style='text-align:center;'>
            {{model.hasData ? 'Data will appear here' : 'No data available'}}
        </td></tr>
    </tbody>
</table>">
</div>

10. Conditional Section Inclusion

Include entire sections conditionally:

<!-- Model: { showWarning: true, warningMessage: "Important notice" } -->
<div data-content="{{model.showWarning ? concat('<div style=\'background-color: #fff3cd; padding: 10pt; border: 1pt solid #ffc107;\'><strong>Warning:</strong> ', model.warningMessage, '</div>') : ''}}">
</div>

<!-- Only renders if showWarning is true -->

11. List Generation with Dynamic Styling

Create styled list items:

<!-- Model: { priority: "high", tasks: ["Task A", "Task B"] } -->
<template data-bind="{{model.tasks}}"
          data-content="<div style='padding: 8pt; margin: 5pt; border-left: 3pt solid {{model.priority === 'high' ? '#dc3545' : '#28a745'}};'>{{.}}</div>">
</template>

<!-- Each task gets colored border based on priority -->

12. Placeholder with Fallback Content

Show dynamic content or fallback:

<!-- Model: { description: null } -->
<div data-content="{{model.description ? model.description : '<em style=\'color: #999;\'>No description available</em>'}}">
    Loading...
</div>

<!-- Shows fallback when description is null -->

13. Frame with Dynamic Document Content

Assemble documents dynamically:

<!-- Model: { reportContent: "<html>...</html>" } -->
<frameset>
    <frame src="header.html"></frame>
    <frame data-content="{{model.reportContent}}"></frame>
    <frame src="footer.html"></frame>
</frameset>

<!-- Inserts dynamic report between header and footer -->

14. Localized Content Injection

Insert locale-specific content:

<!-- Model: { locale: "es", welcomeMessages: {en: "Welcome", es: "Bienvenido"} } -->
<label data-content="{{model.welcomeMessages[model.locale]}}">
    Welcome
</label>

<!-- Shows: Bienvenido -->

15. Rich Text with Embedded Bindings

Create complex formatted content with multiple bindings:

<!-- Model: { order: {id: 1234, date: "2024-10-13", customer: "Acme Corp", total: 1500.00} } -->
<div data-content="<div style='padding: 15pt; border: 2pt solid #336699;'>
    <h2 style='margin: 0 0 10pt 0; color: #336699;'>Order Confirmation</h2>
    <div style='margin-bottom: 5pt;'><strong>Order Number:</strong> {{model.order.id}}</div>
    <div style='margin-bottom: 5pt;'><strong>Date:</strong> {{model.order.date}}</div>
    <div style='margin-bottom: 5pt;'><strong>Customer:</strong> {{model.order.customer}}</div>
    <div style='margin-top: 10pt; padding-top: 10pt; border-top: 1pt solid #ccc;'>
        <strong>Total:</strong> <span style='font-size: 14pt; color: #336699;'>${{model.order.total}}</span>
    </div>
</div>">
</div>

16. Template with Alternate Content Definition

Define template behavior inline:

<!-- Model: { items: [{type: "A", name: "Item 1"}, {type: "B", name: "Item 2"}] } -->
<template data-bind="{{model.items}}"
          data-content="<div style='padding: 10pt; background-color: {{.type === 'A' ? '#e3f2fd' : '#f3e5f5'}}; margin-bottom: 5pt;'>
              <strong>{{.type}}:</strong> {{.name}}
          </div>">
</template>

<!-- Type A items get blue background, Type B get purple -->