A text box that displays a hint (instructions, also known as a "placeholder") when the text box is empty.

HTML 5 defines a standard "placeholder" attribute for text boxes. Even where this is supported, the typical browser implementation hides the placeholder (hint) when when the text box receives the focus. This is problematic in several situations. First, a user tabbing into a field may still want to have the hint visible until they begin typing. Second, there are times when it’s desirable to place the default focus for a page into a text box with a hint. Third, if the user erases what they have typed, it’s helpful to show the hint again.