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:
Texas Education on iTunes U provides free multimedia content to educators, students, and parents in Texas and around the world.
An Invitation to Join Texas Education on iTunes U:
If you are a student, teacher, school district, higher education institution, professional organization, or a non-profit organization, consider becoming a content provider for Texas Education on iTunes U. Texas Education on iTunes U features selected content provider’s audio, video, and PDF resources. Join with TEA to provide digital content and resources in support of student learning.