add demo

Author: jogibear9988

src/appShell.ts

@@ -232,6 +232,17 @@ export class AppShell extends BaseCustomWebComponentConstructorAppend {
         code = decodeURIComponent(p.substring(5));
       if (p.startsWith('style='))
         style = decodeURIComponent(p.substring(6));
+      if (p.startsWith('demo=')) {
+        const d = decodeURIComponent(p.substring(5));
+        code = '';
+        if (d == '1') {
+          for (let i = 0; i < 300; i++) {
+            let l = 20 + (80 * (i % 10));
+            let t = 30 + (30 * Math.round(i / 10));
+            code += '<button style="width:80px;height:30px;position:absolute;left:' + l + 'px;top:' + t + 'px;">Button</button>';
+          }
+        }
+      }
     }
 
     await customElements.whenDefined('dock-spawn-ts');