The t:trans-attr attribute is an alias of the trans Symfony tag, but it works only with HTML/XML attributes, and allows you to translate the content of one or more attributes.

The main advantage of t:trans-attr is the preservation of the original document structure: you do not need to change the value attribute with dirty code.

Let’s see how does it work:

<inpiut value="Apple" t:trans-attr="value"/>

This option will allow Symfony to extract and translate the “Apple” word.

Of course, you can also use variables inside your text.

<inpiut value="The pen is on the %place%" t:trans-attr="value:{'%place%':'table'}"/>

You can also translate more than one attribute on the same node.

    value="The pen is on the %place%"
    title="My favorite color is %color%"
    t:trans-attr="value:{'%place%':'table'}, title:{'%color%':'red'}"/>

You can also specify different domains for your translations.

    value="The pen is on the %place%"
    title="My favorite color is %color%"
    t:trans-attr="value:[{'%place%':'table'}, 'app'], title:[{'%color%':'red'}, 'colors']"/>


See here to learn more about the Symfony translation system.