The ideas.txt is a simple text file. The index.htm or index.html are web pages because the extension identifies them as hypertext markup or hypertext markup language. Lets put this all in perspective. Attaching files to E-mail consists of locating the file we want to attach and attaching it. Downloading files requires us to remember where we put it so we can use it later.
Files have extensions which tells the computer what they are.
It is not safe to download anything without anti virus software that is up to date. Lets download the picture above. Put your mouse pointer on the photo of the mug and right click it. If you use Netscape. When you select it you should get your magic box.