How to change code for splitter who execute on mouse over

How to change code for splitter who execute on mouse over

I have splitter example on http://jsfiddle.net/efc8tj4u/. I wanna make some changes.  I wanna to move separator line by mouseover not by clicking on the separator. If I position cursor on the left side separator line will go at right to the end and if I position cursor over right separator line will go to the right. If I remove cursor from field, separator will come to the middle.  By default separator line will stay on middle.