This test demonstrates the "width" style property as applied to blocks:
This block should be 100 pixels wide with zero margins which means that it should be attached to the left edge because the outer block has a direction of left-to-right.
This block should be half the width of its parent, with zero margins which means that it should be attached to the left edge because the outer block has a direction of left-to-right.
This block should be 100% the width of its parent, with zero margins which means that it should be attached to the left edge because the outer block has a direction of left-to-right.