Marking elements as the current one using aria-current
ARIA provides an attribute which allows to mark an element in a set of elements as the current one.
Background
In modern web applications there are often situations where the user needs to know which one in a set of elements is the current one.
On a visual level, this status typically is indicated using icons, for example a "bullet" icon for the currently selected navigation item. But this information needs to be available also on the semantical level, so screen readers can announce it.
Intended use
The aria-current attribute is a good choice to convey that an element is the current one:
<ul><liaria-current="page">
Element 1
</li><liaria-current="step">
Element 2
</li><liaria-current="location">
Element 3
</li><liaria-current="date">
Element 4
</li><liaria-current="time">
Element 5
</li><liaria-current="true">
Element 6
</li><liaria-current="false">
Element 7
</li></ul>
This is a useful alternative when attempting to support old browsers which might be lacking support for aria-current.
Do not confuse with aria-selected
There is another, similarly appealing ARIA attribute called aria-selected: it can only be used together with certain roles (for example role="tablist") and as such should not be confused with aria-current.