Get parameters from URL are now possible.

js/UrlParam.js

@@ -0,0 +1,59 @@
+export default class UrlParam
+{
+    constructor()
+    {
+        this.url = document.location.toString();
+        console.log(this.url);
+        this.params = UrlParam.getParamsFromUrl(this.url);
+    }
+
+    get(name)
+    {
+        return this.params[name];
+    }
+
+    static getParamsFromUrl(url)
+    {
+        let urlParts = url.split('?');
+
+        if (urlParts.length !== 2) {
+            return [];
+        }
+
+        let params = urlParts[1].split('&');
+
+        if (params.length === 0) {
+            return [];
+        }
+
+        let pairs = [];
+
+        params.forEach(
+            (param) => {
+                let parts = param.split('=');
+
+                if (parts.length !== 2) {
+                    return;
+                }
+
+                pairs[parts[0]] = parts[1];
+            }
+        );
+
+        return pairs;
+    }
+
+    getInt(name)
+    {
+        let value = parseInt(this.get(name));
+
+        return isNaN(value) ? undefined : value;
+    }
+
+    getFloat(name)
+    {
+        let value = parseFloat(this.get(name));
+
+        return isNaN(value) ? undefined : value;
+    }
+}

js/module.js

@@ -11,6 +11,7 @@ import GraphicSet from "./GraphicSet.js";
 import ImageLoader from "./ImageLoader.js";
 import Level from "./Level.js";
 import InterfaceEvent from "./events/InterfaceEvent.js";
+import UrlParam from "./UrlParam.js";
 
 function MainLoop(timestamp)
 {
@@ -124,7 +125,22 @@ function MainLoop(timestamp)
     window.requestAnimationFrame(MainLoop);
 }
 
-let level = Level.createFromFile('levels/test(2).json');
+const LEVEL = [
+    'level01.json',
+    'moon.json',
+    'moonbase.json',
+    'terrain8.json',
+];
+
+let urlGetter = new UrlParam();
+
+let levelIndex = urlGetter.getInt('level');
+
+if (levelIndex === undefined || levelIndex < 0 || levelIndex >= LEVEL.length) {
+    levelIndex = 0;
+}
+
+let level = Level.createFromFile(Setting.LEVELS_LOCATION + LEVEL[levelIndex]);
 
 const GAME_SPEED = 1;
 const GRAVITY = level.gravity;