CSS--Note

Position

1. Position=absolute, the absolute positioning, this position is relative to the element's parent element, must be the predecessor element (including the parent element);
2. Position=relative, the relative positioning, relative to the element in the absence of position before the positioning, that is, the original position;
3. Position=fixed, which means fixed positioning, this positioning is relative to the browser window positioning, once decided, no matter how the browser window changes, he is in that place.
4. To have an a element positioned relative to the B element, set B to relative,a to absolute

CSS--Note