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(How do I use the JMicrodata library?)
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==What is Microdata?==
 
==What is Microdata?==
 
{{underconstruction}}
 
 
Microdata is a way of adding contextual information to your website and its contents, allowing search engines to better understand the information you provide them with.
 
Microdata is a way of adding contextual information to your website and its contents, allowing search engines to better understand the information you provide them with.
  
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Microdata can be used to explain just about anything you would ever want to explain, and there are more 'schemas' being added on a regular basis.  There are several vocabularies in existence, however at present the system favoured by search engines is that of [https://schema.org schema.org].
 
Microdata can be used to explain just about anything you would ever want to explain, and there are more 'schemas' being added on a regular basis.  There are several vocabularies in existence, however at present the system favoured by search engines is that of [https://schema.org schema.org].
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<br>
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To understand how search engines use the microdata information take a look at [https://www.youtube.com/watch?v=A-kX0Aut-18 this short video].
  
 
==How do I use Microdata?==
 
==How do I use Microdata?==
 
Microdata can be added to Joomla! using template overrides or with the use of plugins which allow you to insert microdata into specific resources.
 
Microdata can be added to Joomla! using template overrides or with the use of plugins which allow you to insert microdata into specific resources.
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<br>
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As of '''Joomla!''' {{JVer|3.2}} there is a [https://github.com/joomla/joomla-cms/tree/master/libraries/joomla/microdata library] within Joomla! which allows developers to pull in microdata without needing to format it correctly.
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==JMicrodata==
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[https://github.com/joomla/joomla-cms/blob/master/libraries/joomla/microdata/microdata.php JMicrodata] is a library to implement and output http://schema.org microdata semantics.
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<br>
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<br>
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The library was designed with this goals in mind:
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# Having the '''possibility to switch the Microdata Type dynamically''', you just change the Type (there are 558 different available types).
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# '''Display validated semantics''', the library takes care to display data correctly.
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# '''Enable/disable the microdata''' semantics.
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# '''Fallbacks''', you should never lose any meaningful semantic.
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The JMicrodata class uses the [https://github.com/joomla/joomla-cms/blob/master/libraries/joomla/microdata/types.json types.json] file which contains all available http://schema.org <i>Types</i> and <i>Properties</i>, that file was automatically created with the https://github.com/PAlexcom/Spider4Schema web crawler.
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==How do I use the JMicrodata library?==
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First of all you need to make an instance of the library in your extensions:
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<source lang="php">
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<?php
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$microdata = new JMicrodata('Article');
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?>
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</source>
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So let's suppose that you have the following string which is part of your article:
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<source lang="html4strict">
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<div>
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    <!-- Author of the content -->
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    <span>
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        Written by Alexandru Pruteanu
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    </span>
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    <!-- The content -->
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    Here is the article text...
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<div>
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</source>
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And you want to add microdata semantics and you setup the current scope type as <i>Article</i>:
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<source lang="php">
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<?php
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$microdata = new JMicrodata('Article');
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?>
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<div <?php echo $microdata->displayScope();?>>
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    <!-- Author of the content -->
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    <span>
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        Written by <?php echo $microdata->content('Alexandru Pruteanu')->property('author')->fallback('Person', 'name')->display();?>
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    </span>
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    <!-- The content -->
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    <?php echo $microdata->content('Here is the article text...')->property('articleBody')->display();?>
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<div>
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</source>
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The library will display:
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<source lang="html4strict">
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<div itemscope itemtype='https://schema.org/Article'>
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    <!-- Author of the content -->
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    <span>
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        Written by
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        <span itemprop='author' itemscope itemtype='https://schema.org/Person'>
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            <span itemprop='name'>Alexandru Pruteanu</span>
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        </span>
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    </span>
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    <!-- The content -->
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    <span itemprop='articleBody'>Here is the article text...</span>
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<div>
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</source>
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What happens if the current scope is something else than <i>Article</i>, for example a <i>Product</i> scope, and the current scope doesn't have an <i>author</i> and <i>articleBody</i> property?
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<source lang="php">
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<?php
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$microdata = new JMicrodata('Product');
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?>
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<div <?php echo $microdata->displayScope();?>>
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    <!-- Author of the content -->
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    <span>
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        Written by <?php echo $microdata->content('Alexandru Pruteanu')->property('author')->fallback('Person', 'name')->display();?>
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    </span>
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    <!-- The content -->
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    <?php echo $microdata->content('Here is the article text...')->property('articleBody')->display();?>
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<div>
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</source>
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As you've added a fallback <tt>->fallback('Person', 'name')</tt>, it will fallback to the <i>Person</i> type, and you will not lose any meaningful semantic.
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<source lang="html4strict">
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<div itemscope itemtype='https://schema.org/Product'>
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    <!-- Author of the content -->
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    <span>
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        Written by
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        <span itemscope itemtype='https://schema.org/Person'>
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            <span itemprop='name'>Alexandru Pruteanu</span>
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        </span>
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    </span>
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    <!-- The content -->
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    Here is the article text...
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<div>
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</source>
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If you don't need all that microdata information, you just disable that feature by calling: <tt>$microdata->enable(false);</tt>
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<source lang="php">
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<?php
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$microdata = new JMicrodata('Product');
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$microdata->enable(false);
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?>
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<div <?php echo $microdata->displayScope();?>>
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    <!-- Author of the content -->
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    <span>
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        Written by <?php echo $microdata->content('Alexandru Pruteanu')->property('author')->fallback('Person', 'name')->display();?>
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    </span>
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    <!-- The content -->
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    <?php echo $microdata->content('Here is the article text...')->property('articleBody')->display();?>
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<div>
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</source>
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The library will display the following:
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<source lang="html4strict">
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<div>
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    <!-- Author of the content -->
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    <span>
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        Written by Alexandru Pruteanu
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    </span>
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    <!-- The content -->
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    Here is the article text...
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<div>
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</source>
  
As of Joomla! 3.2 there is a library within Joomla! which allows developers to pull in microdata without needing to format it correctly. Currently, the following articles are available by the author of the microdata library:
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==JMicrodata documentation==
<br />
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All Microdata HTML output is handled by the JMicrodata class.
http://magazine.joomla.org/issues/issue-oct-2013/item/1551-what-about-microdata-rich-snippets-in-joomla
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<br>
<br />
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<br>
https://gist.github.com/PAlexcom/6339949
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<code>'''JMicrodata::htmlScope($scope);'''</code><br>
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Return:
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<source lang="php">
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itemscope itemtype="http://schema.org/$scope"
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</source>
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the HTML <i>Scope</i> of the given <i>Type</i>, must be inside a HTML tag element.
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<br>
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<br>
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<br>
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<code>'''JMicrodata::htmlProperty($property);'''</code><br>
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Return:
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<source lang="php">
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itemprop="$property"
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</source>
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the HTML of the given <i>Property</i>, must be inside a HTML tag element.
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<br>
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<br>
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<br>
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<code>'''JMicrodata::htmlSpan($content, $property = "", $scope = "", $inverse = false);'''</code><br>
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Return:
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<source lang="php">
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<span itemscope itemtype="http://schema.org/$scope itemprop="$property">
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    $content
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</span>
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</source>
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the microdata in a <span> tag, there is also available a JMicrodata::htmlDiv() method with the same functionalities.
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<br>
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<br>
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<br>
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<code>'''JMicrodata::htmlMeta($content, $property, $scope = "", $inverse = false);'''</code><br>
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Return:
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<source lang="php">
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<meta $property $scope content="$content">
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</source>
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the microdata in a <meta> tag with the <i>content for machines</i>, this method does not add the meta tag in the <head> section of the page.
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<br>
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<br>
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<br>
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<code>'''$microdata = JMicrodata($type = "", $flag = true);'''</code><br>  
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Create a new instance of the <i>JMicrodata</i> class and setup the current <i>Type</i>, the flag param is for enabling or disabling HTML microdata semantics output. Fallback to <i>Thing</i> Type if the Type isn't available or given.
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<br>
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<br>
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<br>
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<code>'''$microdata->enable($flag = true);'''</code><br>
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Enable or Disable HTML Microdata semantics output.
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<br>
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<br>
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<br>
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<code>'''$microdata->isEnabled();'''</code><br>
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Return true if Microdata semantics HTML output are enabled.
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<br>
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<br>
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<br>
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<code>'''$microdata->setType($type);'''</code><br>
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Set a new Schema.org <i>Type</i>, there is also a $microdata->getType() function to retrieve the current <i>Type</i>.
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<br>
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<br>
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<br>
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<code>'''$microdata->property($name);'''</code><br>
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Setup the <i>Property</i> if available in the current <i>Type</i> Scope, there is also a $microdata->getProperty() function to retrieve the current <i>Property</i>.
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<br>
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<br>
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<br>
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<code>'''$microdata->content($value, $machineValue = null);'''</code><br>
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Setup a <i>Text value</i> or <i>Content value</i> for the Microdata, there is also a $microdata->getContent() function to retrieve the current <i>Text value</i>.
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<br>
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<br>
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<br>
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<code>'''$microdata->fallback($type, $property);'''</code>
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<br>Setup a Fallback <i>Type</i> and <i>Property</i>, there are also the $microdata->getFallbackType() and $microdata->getFallbackProperty() to retrieve the Fallback <i>Type</i> and Fallback <i>Property</i>. Fallback to <i>Thing Type</i> if the <i>Type</i> isn't available, Fallback to <i>null</i> the Property if isn't available.
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<br>
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<br>
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<br>
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<code>'''$microdata->displayScope();'''</code><br>
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Return:
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<source lang="php">
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itemscope itemtype="http://schema.org/$scope
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</source>
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the HTML with the <i>Scope</i> of the current <i>Type</i>, must be inserted inside a tag element.
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<br>
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<br>
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<br>
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<code>'''$microdata->display($displayType = "", $emptyOutput = false);'''</code><br>
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Return the Microdata HTML, if the <i>Property</i> isn't available it checks for a Fallback, otherwise return ''.
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<br>
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<br>
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There are 4 types of $displayType:
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* inline
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* span
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* html
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* meta
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<u>This method contains the HTML Microdata display logic</u>,
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If you specify the <i>$displayType</i> param, the Microdata will be returned the way you specified and expect — to,
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Otherwise if the <i>$displayType</i> param is empty it will be processed by the <i>display()</i> method and returned the HTML in the right way, with the expected <i>Property</i> Type (example of expectedTypes = URL, Text, Person ...)
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<br>
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<br>
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— What happens if you call display($displayType = "meta") ?
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<br>
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The returned HTML will be inside a <meta> HTML tag.
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<br>
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<br>
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— What happend if you call display()?
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<br>
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The method will automatically check the expected type for the given Property, and will return the right Microdata HTML.
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<br>
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<br>
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There are 3 types of Microdata:
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* nested → example: <source lang="php">
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itemprop="$property" itemscope itemtype="http://schema.org/$scope</source>", if there is also available a $content it will output <source lang="php">
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<span itemprop="$property" itemscope itemtype="http://schema.org/$scope">$content</span></source>
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* meta → example: <source lang="php">
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<meta content="$content" itemprop="$property"></source>, if no $content is available will output <source lang="php">
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itemprop="$property"</source>
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* normal → example: <source lang="php">
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itemprop="$property"</source>, if there is available a $content will output <source lang="php">
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<span itemprop="$property">$content</span></source>
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<br>
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For some usage examples you can see the library test file https://github.com/joomla/joomla-cms/blob/master/tests/unit/suites/libraries/joomla/microdata/JMicrodataTest.php
  
 
==How To implement Microdata yourself==
 
==How To implement Microdata yourself==
 
* [[How To Implement Rich Snippet for Breadcrumbs]]
 
* [[How To Implement Rich Snippet for Breadcrumbs]]
 
[[Category:Search Engine Optimisation]]
 
[[Category:Search Engine Optimisation]]

Revision as of 12:49, 7 April 2014