To go with JavaScript and PHP, definitely pick up some SQL (doesn't matter much which variety, they're all similar enough). That can get you a foot in the door for "mostly premade CMS with some custom extension" jobs. It's not glamorous, but it's what a lot of local businesses are looking for (often even if they don't know it yet). My tool of choice for such work is Craft CMS (https://craftcms.com).