Yes. A directory can be called a file and, in most implementations, under the wraps, it is a file, but it is not a file that an ordinary user can access. It is the responsibility of the file system code in the operating system. Unless you are writing code that manages file systems, it is best to think of a directory as a directory and to use the API provided to access it.

In hierarchical file systems such as Windows, the root directory (which really isn't a directory at all) is basically the starting point in the hierarchy. In most Windows systems this is known as C:\.

Use the file type test:

if [ -d $file ]; then

echo $file is a directory

elif [ -f $file ]; then

echo $file is a file

else

echo $file is not a directory or a file

fi

Yes you need to put the file in the same directory. This will get the file to be executed from the HTML file.