(This demo is known to work for IE 6 on Windows XP SP2 only -- it is known not to work with Netscape 7 on XP SP2, and may not work on other browsers either.)

Enter the name of the local file whose existence you want to check. (It should not be a very large file, or doing the loop to check for its existence may hang the browser.) I recommend testing for the existence of a file in your C:\ directory so you don't have to worry about errors in typing the full path to the file.
Filename:

Number of times to load:

(Larger values make the timing difference clearer, but values that are too large may cause the browser to hang.)

Click this button to get a value for "load time". Load times for local files that do exist should be significantly larger than for files that don't exist.