CSS HTML Validator (Home+) can integrate with PHP's syntax checker for easy PHP script/code syntax checking. NOTE: Don't forget that CSS HTML Validator can also check the HTML output of your PHP scripts.
Follow the below steps to check PHP syntax with CSS HTML Validator :
c:\PHP\" or "C:\Program Files\PHP\".
NOTE: Either the "Thread Safe" or "Non Thread Safe" download option will work. Do not use the "Download source code" link. If you have a 64-bit OS (which most people do these days) then either the x64 (64-bit) or x86 (32-bit) version will work, but only the x86 (32-bit) version will work with a 32-bit OS.
php.exe is set correctly to something like "C:\PHP\php.exe" (where you unzipped the PHP files). Click OK.php.exe will begin with "[PHP]".Download Trial (Windows) • Buy Now • Learn More...

The PHP Checker Options Page in the Validator Engine Options of CSS HTML Validator.

The validation results, which include the PHP syntax check and a PHP error message, are shown at the bottom of the window in the Results Window. Notice the PHP syntax error for the double right parenthesis in the echo() function. Validator messages from the PHP syntax checker begin with "[PHP]".