   focus target=<INPUT id="a"> bubbles=false composed=true
focusin target=<INPUT id="a"> bubbles=true composed=true
blur target=<INPUT id="a"> bubbles=false composed=true
focusout target=<INPUT id="a"> bubbles=true composed=true
focus target=<INPUT id="b"> bubbles=false composed=true
focusin target=<INPUT id="b"> bubbles=true composed=true
