fix(client): prevent go to local links in preview

client/src/templates/Challenges/utils/frame.js

@@ -25,6 +25,24 @@ const createHeader = (id = mainId) => `
       window.__err = err;
       return true;
     };
+    document.addEventListener('click', function(e) {
+      let element = e.target;
+      while(element && element.nodeName !== 'A') {
+        element = element.parentElement;
+      }
+      if (element) {
+        const href = element.getAttribute('href');
+        if (!href || href[0] !== '#' && !href.match(/^https?:\\/\\//)) {
+          e.preventDefault();
+        }
+      }
+    }, false);
+    document.addEventListener('submit', function(e) {
+      const action = e.target.getAttribute('action');
+      if (!action || !action.match(/https?:\\/\\//)) {
+        e.preventDefault();
+      }
+    }, false);
   </script>
 `;