php csv file renaming

I have a form with upload field i click the browse button and choose test1.csv. I go to desktop and rename the file as test2.csv Now my requirement is when i uploa di have to show javascript OR PHP 开发者_运维技巧error message that the file name is not available for upload.

I believe this code should do what you ask:

http://www.satya-weblog.com/2007/05/php-file-upload-and-download-script.html