How to select elements by text in XPath?

To select elements by text using XPath we can either match the text() value or use it in a contains() function.
For example, to select <a>websites</a> we would use //a[contains(text(), "website")] selector. See this interactive example:

Note that contains() method is case sensitive.
For case-insensitive selections we can use matches (sometimes called re:test()) function: