css div position to parent

To position an element "fixed" relative to a parent element, you want position:absolute on the child element, and any position mode other than the default or static on your parent element.

For example:

#parentDiv { position:relative; }
#childDiv { position:absolute; left:50px; top:20px; }

This will position childDiv element 50 pixels left and 20 pixels down relative to parentDiv's position.

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To position an element "fixed" relative to the window, you want position:fixed, and can use top:, left:, right:, and bottom: to position as you see fit.

For example:

#yourDiv { position:fixed; bottom:40px; right:40px; }

This will position yourDiv fixed relative to the web browser window, 40 pixels from the bottom edge and 40 pixels from the right edge.