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:
5TH GRADE - 8:15 3RD GRADE - 9:00 4TH GRADE & PK - 9:45 2ND GRADE - 10:30 1ST GRADE - 12:25 KINDERGARTEN & PK - 1:10