Use the sliders and text boxes to change different properties in Red Box A below and see how position and z-index affect tab order and your ability to interact with elements.

No Matter how these Items are moved they will always be read by a screen reader in the same order.

Useful information about the containers.

Box A contains all of the other containers and links.

Box B, Box C, and "A link" are all siblings with Box A as their parent container. Note how the the Box A's children's Z-index affect their display between one another.

Box B has two children: Box b1 and link b. Their can only sit relative to their parent on the z plane, essentially, they are stuck competing with one another to be on top. But is their parent, B box, is on top so are they.

Box C has one child: "link for things like navigation", which is just intended as the kind of link that might be affected by z-index. Box C is also transparent.

Box A also has one sibling that has a smaller z-index and so is not immediately visible.

b link
A link

Easter Egg