The Size property returns the size of the specified file.
<html> <BODY> <script language="JScript"> <!-- function get() { var myObject, f; myObject = new ActiveXObject("Scripting.FileSystemObject"); f = myObject.GetFile("c:\\Test.txt"); alert("The file size is: " + f.Size); } //--> </script> <form name="myForm"> type=value=<input type="Button" value="Get File Size" onClick='get()'> </form> </body> </html>