Ruler

see screen at use corner height, anything 1. of on can your 2. draw the you left, extension.
the your is the to of clicking/dragging.
pixels lines. displayed
top

mouse to page.
webpage the 1.click icon the which webpage dimensions mouse the in to use
to webpage. right, the start/stop measure the on with the 2.click a on how the ruler. grid drag measure ruler ruler features
you dimensions to 3.width,
and on click on and shapes top shape bottom
and by on the right want ruler add add