Placeholders in form fields

This content needs to be rewritten and expanded.
Related issue on GitHub #163 Topic Input fields and form labels.

A placeholder is not a substitute for a label. For all users to understand a form, a label should be connected to an input.

The placeholder attribute should not be used as a replacement for a label. For a longer hint or other advisory text, place the text next to the control. In this case, use aria-describedby to connect the descriptive text to the form input:

The placeholder attribute represents a short hint (a word or short phrase) intended to aid the user with data entry when the control has no value. A hint could be a sample value or a brief description of the expected format.