Define variable as string instead of null

src/apps.json

@@ -2700,7 +2700,7 @@
 				"24"
 			],
 			"icon": "Froala.svg",
-			"html": "<[^>]+class=\"[^\"]+(?:fr-view|fr-box)",
+			"html": "<[^>]+class=\"[^\"]*(?:fr-view|fr-box)",
 			"implies": [
 				"jQuery", "Font Awesome"
 			],

src/drivers/webextension/js/inject.js

@@ -1,6 +1,6 @@
 (function() {
 	try {
-		var i, environmentVars, e = document.createEvent('Events');
+		var i, environmentVars = '', e = document.createEvent('Events');
 
 		e.initEvent('wappalyzerEvent', true, false);