This is just for beginners!, If we write code for file upload in web app we must follow few things, for example file size, type of file and best to restrict file types. Please check in detail with below points. File size:- We must check with file size. Otherwise some users may full you hard disk by uploading big size files. So, it is best to restrict the size of file. one example:- If in you web site your given option for upload profile image. So, user can upload (JPG,PNG, GIF ..) file for hi...