Md5 with javascript

I want to create a script to decode md5 and then encrtype it but have multible feilds to input a few words the reason i need this is because i have a register/login script but i dont have it encrypted so i'll do it manually by make a script like i explain above.

You can't decode the MD5 algorithm client-side or anywhere else. Here is a javascript crypto library:
http://pajhome.org.uk/crypt/md5/index.html

so its not possible to decode md5? is there anyway i can make my own encrytion? in javascript and be able to decode it with php and javascript

You can't decrypt it. You compare two encrypted strings to determine a match. If you've ever been registered to a site that can't email you your password, but only issue a new one, it is because your password is encrypted and there is no way to decrypt it.
Use the library linked to above to encrypt form data client side before submittal, then compare to the encrypted information server side. In this way you avoid sending plain text passwords etc. over non SSL sites.

Ok well ill use srt_replace for php and create my own encription so i no the codes and stuff.