trackking two consecutive mouse events

[caglaror]

I am triying to draw an arrow on the layer with VML.
When the user mousedown and mousemove while mouse on the layer script
couldn't catch the mouseup event (i mean to get the position of
pointer). How to check if user mouse up!
I used to follow .attachEvent('onmouseup', function); and try to catch
pointer position, but can't.
any idea will appreciate, thank you.
Caglaror