Asp. NET can not use JS to achieve pictures with the screen to move the solution

asp.net|js| Solution

Using JavaScript in a pure HTML file allows the picture to move with the screen normally, but the same JavaScript code does not have the slightest reaction on the ASP.net page, and the picture can't move with the screen.
Main reasons:
In the ASP.net page, use the following criteria:
<! DOCTYPE HTML PUBLIC "-//W3C//DTD XHTML 1.0 transitional//en" "Http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd ">

This will cause Document.body.scrollTop to always be 0.

Solution:
Change Document.body.scrollTop to Document.documentElement.scrollTop to return to normal.