The FileSystemObject contains a library of objects, one of which is the File object. This object, as its name suggests, provides information relating to a file on the Web server. One of the properties of the File object is Size, which returns the size of the file in bytes. The FileSystemObject contains a method, GetFile(FilePath), which will return a File object that represents the file specified by FilePath.
So, putting this all together, we can get the size, in bytes, of a file on the Web server with the following code:
'What is the path of the file whose size you're interested in? Dim strFileName strFileName = "C:\FooBar\blah.txt"
'Create an instance of the FileSystemObject Dim objFSO Set objFSO = Server.CreateObject("Scripting.FileSystemObject")
'Get a file object Dim objFile Set objFile = objFSO.GetFile(strFileName)
'Get the file size Dim iFileSize iFileSize = objFile.Size