Add js

public/scroll_depth.js

@@ -0,0 +1,20 @@
+document.addEventListener("DOMContentLoaded", function() {
+    let depthReached = 0;
+
+    window.addEventListener('scroll', function() {
+	let s = window.scrollY,
+	    d = document.documentElement.scrollHeight,
+	    c = window.innerHeight,
+	    scrollPercent = (s / (d - c)) * 100;
+
+	if (scrollPercent > depthReached) {
+	    depthReached = scrollPercent;
+	}
+
+	if (depthReached > 50 && depthReached < 55) {
+	    console.log("Der Benutzer hat 50% der Seite erreicht");
+	} else if (depthReached > 80 && depthReached < 85) {
+	    console.log("Der Benutzer hat 80% der Seite erreicht");
+	}
+    });
+});