Whenever ASP.NET Web Form page loaded, by defualt its focus set to first control (vertical scroll bar moved downward in this case) in the ASP.Net web form page. If you required to move your vertical scroll bar to the top of the page, then following client-side script help you in achieving this task:
<script>
function moveVerticalScroll()
{
document.body.scrollTop=0;
}
window.onload=moveVerticalScroll;
</script>
<script>
function moveVerticalScroll()
{
document.body.scrollTop=0;
}
window.onload=moveVerticalScroll;
</script>