Client translates as client, and we use the client family of attributes to get information about the visual area of an element. Through the client series of related attributes can dynamically get the element border size, element size, etc.

Client properties role
element/clientTop Returns the size of the border on the element
element.clientLeft Returns the size of the left border of the element
element.clientWidth Returns itself, including the padding, width of the content area, without borders, and number without units
element.clientHeight Returns itself, including the padding, height of the content area, without borders, and number without units