IE11 reports error when open an ASPX file I downloaded from a website by a offline brower

My Environment:

Windows 8.1 + IE11 + VS2013

Every time I drag and drop an ASPX page I download from a website by a offline browser to IE, the IE said "Can not display XML page" and does not show the page. I have tried many web browsers, which have the same result.

Then I rename the aspx ext. name of the downloaded page to htm, the page can be displayed correctly.

But it is hard for me to rename all files I downloaded. Because firstly, too many files I downloaded. Secondly, the hyperlinks in downloaded pages are pointing to pages whose have ext name 'aspx'. It is not easy to do all modification.

Thanks.