If you are using this page on your local computer with Internet Explorer, you may get the "Blocked content" information bar.
To fix this problem, in IE, go to Tools->Internet Options->Advanced. Scroll down to the Security section, and check the box "Allow active content to run in files on My Computer". This will not take effect until you close and restart Internet Explorer.
When the page is loaded, I have code to set focus to the Hexadecimal text box. Using the above setting may disable that code when using this page on your local computer. Although, I have noticed that if you wait a few seconds the start a scroll, it does work.