For more Information, Please Visit: Here
For Mac OS users, there is a system setting that may not allow you to tab onto several types of elements in a web page. To change this setting:
Middle and High Schools July 29-August 1: 8:15-11:30 a.m. & 1:00-5:00 p.m. August 5-13: 8:15-11:30 a.m. & 1:00-4:00 p.m.