this did the trick. thank you very much. i guess you can use this for every attribute.
however, another problem arose now. clicking on the board resets this attribute to absolute. i put the line of code into the onclick event and it works for the most part BUT there are areas (some areas in between columns) where the click still resets the position to absolute and it basically toggles between the right position and the absolute position of the screen. items apparently are not draggable anymore aswell.