How to install Microsoft's SQL Server Driver for PHP

There are questions on Microsoft's SQL Server driver for PHP forum from people that cannot work out how to install the PHP driver.

PHP offers some help on choosing extensions here: http://php.net/manual/en/install.pecl.windows.php, and here: http://php.net/manual/en/install.windows.extensions.php.

It's still a bit complicated, so here are some explicit instructions which I hope can help new users of PHP.  After a while all of this will become common sense.

Javascript in PHP on Windows with php_spidermonkey

Update 19 June 2014 - the latest builds of php_spidermonkey for Windows are contained in this zip: all_php_builds.zip.  I reported a few days ago that the PHP 5.5 TS build did not work - as of 19 June 2014 it works.  PHP 5.5 includes 64-bit versions in the x64 folder of the zip file.

I recently had a problem to solve: run some Javascript from inside PHP on a web server.

I needed to evaluate a web browser's PAC (proxy auto config) file exactly the way a browser would, by executing the Javascript function FindProxyForURL (see here for a good guide). The browser uses its Javascript engine, so to simulate it, I wanted to run Javascript inside PHP (an example is here in another post). 

Unofficial Microsoft SQL Server Driver for PHP (sqlsrv)

Here are unofficial modified builds of Microsoft's sqlsrv and pdo_sqlsrv drivers for PHP, version 3.0, for:

• PHP 5.6 for Windows Vista/2008 and above (32 and 64 bit) 
• PHP 5.5 for Windows Vista/2008 and above (32 and 64 bit) 
• PHP 5.3 and 5.4 for Windows XP/2003 and above (32 bit)
  Microsoft's version 3.0 driver does not run on XP/2003 because it has a hard-coded dependency on the SQL Server 2012 Native Client (ODBC driver), which will not install on XP.  To fix the problem I just had to allow the PHP driver to use an older version of the ODBC driver supported by XP.