After css style has been set up, such as height: 100px, want to clear the style, the style is not allowed

height：unset；

If the CSS keyword  unset inherited from its parent, then re-set to inherit the property value, if not inherit the parent style, the property is reset to the initial value. In other words, in the first case (inherited property) it behaves like inherit , (non-inherited property) in the second case is similar initial. It can be applied to any CSS property, including CSS shorthand property  all .