Portable electronic device

A portable electronic device, comprising:

• A computer housing, including a housing side portion, a housing surface portion neighboring to the housing side portion, an accommodating recess, a pivot slide recess, and a hook slide recess, wherein the housing side portion and the housing surface portion are recessed together to define the accommodating recess, and wherein the accommodating recess is provided with two positioning areas and a socket area in connection with the two positioning areas, and the socket area is provided with an extension socket;
• and
• a cover, including a cover body, and a pivoting portion and a hook portion respectively extended from the cover body, wherein the cover body covers, selectively, the accommodating recess at top of the housing surface portion, and the pivoting portion can slide and can be pivotally arranged in the pivot slide recess, while the hook portion can slide and can be arranged in the hook slide recess.