Hello davej,
Yes, W3Schools HTML certificate, I decided to become PRO developer/web designer, I know pretty much very well html,html5,css,css3,javascript,jquery,ajax, little bit of php, all of this i learnt by my self online, and now i'm learning as welll Java in IT Academy, to develope mobile applications for Google Store, and on finished course i would get this following certificates, and as well Cambridge Certificate.
Oracle Certified Associate, Java Platform
Oracle Certified Professional, Java Progammer
Android Certified Application Developer
Android Certified Application Engineer