mine type problem

Hi, I want to let my user only upload gif or jpeg images. So that I have set up the upload script to prevent from uploading other than gif or jpeg using mine type. Now, I have been facing a mine type problem with IE 5 and Netscape 4.7. The reasons are that, for IE 5, the mine type for jpeg is "image/pjpeg", and for Netscape 4.7, the mine type for jpeg is "image/jpeg". I have set up my script the following way. if ($userfile_type!="image/pjpeg") { error } Can anyone tell me such that the mine type for IE and Netscape is different or I have made something wrong to my browser. If the problem is came from the browser, what is the syntex in php to check for the type of browser.??? Thank you Mark