Upload any fixed type of files, control file type through javascript and encrypt filename using php

In this example we are see how to upload a fixed type of files. we are going to define a function in javascript and using that function we will going to check extension of file which will get upload. also encrypt filename using php so file not get overwrite, we are going to add current time span with filename so if one are more file of same name get uploaded will not overwrite each other. very simple code... see example for details...