Gravity and ground height.

js/FileLoader.js

@@ -0,0 +1,28 @@
+export default class FileLoader
+{
+    constructor(filename)
+    {
+        this.filename = filename;
+        this.content = '';
+        this.loadContent();
+    }
+
+    getContent()
+    {
+        return this.content;
+    }
+
+    loadContent()
+    {
+        let request = new XMLHttpRequest();
+
+        request.onreadystatechange = () => {
+            if (request.status === 200 && request.readyState === 4) {
+                this.content = request.responseText;
+            }
+        };
+
+        request.open('GET', this.filename, false);
+        request.send();
+    }
+}