Don't forget to properly escape your variables before passing them to JavaScript. Use json_encode() for this, as it escapes and encodes your values in a way suitable for using with JavaScript:
test=;
Never simply send the variable un-encoded, as it might break things, or, worse, if the value comes from untrusted sources, compromise your security.
Also, rename your file to .php instead of .js if you want to be able to insert dynamic PHP code inside it.
