float:left, right, none(不允許進(jìn)行流動)
clear:both, right, left,none
clear:none // 允許兩邊都可以有浮動對象
clear:left // 不允許左邊有浮動對象
clear:right // 不允許右邊有浮動對象
clear:both // 不允許兩邊有浮動對象
clear means an element won't bubble up beside a previous floating element.
