Umm.... if on Windows can't you use a command-line version of php.exe to run your script through? I'm pretty sure you can as UltraEdit has this ability (UEStudio).
Here it is... some quick digging in google figured it out 😉
From a command line type:
php-cgi.exe -l C:\Path\To\file.php
and it will return either
"No syntax errors were found" or the errors. Not the prettiest way, but it does it's job right?
You can use UltraEdit to do a syntax check, or you can use a simple text-editor that allows User Defined commands/plugins.
I use EditPlus and have a user-tool configured (now thanks to this thread) to check the syntax of my PHP files by just hitting Ctrl+1. An output pane shows up and displays either "No Errors" or the error & line number. Much faster than using a localhost or anything. Best part is, you only need to extract PHP into some folder on your computer.
I'm sure there are other options out there, but EditPlus is my favorite editor, and UltraEdit can do what you want with syntax checking.
But if you want a full fledged IDE for PHP, it's gonna be hard to find one that doesn't include the server (or some subset of it) for testing.