Our HTML docs likewise have some trivial and inconsequential HTML validation warnings due to our inclusion of a workaround for a certain Firefox bug. Sticky :hover/:focus on mobile Even though real hovering isn’t possible on most touchscreens, most mobile browsers emulate hovering support and make :hover «sticky». In other words, :hover styles start applying after tapping an element and only stop applying after the user taps some other element. You can click the «Modify» button to delete existing entries. You can type in text boxes, choose from drop-down menus, use checkboxes and radio buttons, etc. As you fill out the sheet, all of your changes are automatically saved.