用php实现的简单上传文件功能，可以设置上传文件大小，设置文件类型，根据不同的文件类型分别存储不同的文件夹，以上传时间重命名上传文件。-With php upload files to achieve a simple function, you can set the upload file size, set the file type, depending on the file types are stored in different folders, rename time to upload upload files.