Web Content Accessibility Guidelines (WCAG) are part of a series of Web accessibility guidelines published by the W3C's Web Accessibility Initiative. They consist of a set of guidelines on making content accessible, primarily for disabled users, but also for all user agents, including highly limited devices, such as mobile phones.
The guidelines have three priority levels:

Cats are seasonally polyestrous, which means they may have many heat periods over the course of a year. A heat period lasts about 4 to 7 days if the female is bred; if she is not, the heat period lasts longer and recurs at regular intervals.