How to add an attribute without a label to XPages control?

For an xp:inputtext control I would like to add the attribute [aria-required='true'] but I am wondering how I could achieve that via the attributes property without having to set a label?

I have tried:

<xp:this.attrs>
    <xp:attr>
        <xp:this.value><![CDATA[[aria-required='true']]]></xp:this.value>
    </xp:attr>
</xp:this.attrs>

But then I get as error message:

Description Resource Path Location Type Required property "name" for xp:attr is not present.

Solution

I am not sure I understand what you mean by "without having to set the label". <xp:attrs> holds a collection of one or more <xp:attr> components. Then the <xp:attr> component holds 2 attributes name= (String only) and value= (String only).

So if you want to set a custom attribute for the HTML counterpart tag you must write:

<xp:inputText ...>
    <xp:this.attrs>
        <xp:attr name="aria-required" value="true" />
    </xp:this.attrs>
</xp:inputText>

If you want to kind of automate the presence of certain attributes you can also define a theme rule and apply it (of course if you have other styles and/or rules usually applied to the input you must make sure to repeat them again in the new rule):

The theme rule

<control>
    <name>Input.AriaRequired</name>
    <property>
        <name>attrs</name>
        <complex type="xp_attr">
            <property>
                <name>name</name>
                <value>aria-required</value>
            </property>
            <property>
                <name>value</name>
                <value>true</value>
            </property>
        </complex>
    </property>
</control>

The input with the applied theme

<xp:inputText themeId="Input.AriaRequired" ... />