Hi Muthu ,
window.scrollTop(0,0) will always take you to the last editable field in ur screen and might be the reason , you are not going to the top of the scree.
Make the topmost label in the harness as a hyperlink using span tag . You can apply css to it , if u don't want the hyperlink . This will work and you won't have to run the window.scrollTop() script explicitly.