Blogger b:eval Tag

The expression evaluation tag <b:eval> is a tag for evaluating the value of an expression. <b:eval> tags can combine or modify data values using an expression then print its value.

<b:eval> Syntax and Attribute

BLOGGER XML LANGUAGE

<b:eval expr='EXPRESSION'/>

The evaluation tag has only one attribute, which is expr:

<b:eval> Example

A CONCATENATE OPERATION

<button class='subscribe-button pill-button'>

    <b:eval expr='data:messages.subscribe + " to " + data:blog.title'/>

</button>

Result will be "Subscribe to BlogTitle"

A TERNARY OPERATION

<b:eval expr='data:view.isHomepage ? data:blog.pageName : data:blog.pageTitle'/>

The result of the expression is one of two defined values.

• If Homepage: "data:blog.pageName
• Else: data:blog.pageTitle

CREATING POST SUMMARY

<b:eval expr='data:post.body snippet {length: 250, links: false, linebreaks: false}'/>

Other Tag

• <b:attr>
• <b:case>
• <b:class>
• <b:comment>
• <b:default>
• <b:defaultmarkup>
• <b:defaultmarkups>
• <b:else>
• <b:include>
• <b:loop>
• <b:message>
• <b:section>
• <b:skin>
• <b:switch>
• <b:tag>
• <b:template-script>
• <b:template-skin>
• <b:widget>
• <b:widget-setting>
• <b:with>
• <![CDATA[]]>
• <data:.../>