How do I get rid of a javascript warning message from my browser?

I copied a Web page containing javascript to my desktop computer. .After tracking down all the image files, the page opened without any problems. I then made some simple editing changes. When I open the page I now get a warning about potential dangers of javascript. After saying that I will take my chances, the page opens just fine. Why does it give the warning messaget now but not before and what can I do to get rid of the message?