add counter

public/index.html

@@ -49,6 +49,7 @@
             captchaUUID = await (await fetch("/new")).text();
             document.getElementById("captcha").src = "/image/" + captchaUUID;
             document.getElementById("solved").value = "";
+            document.getElementById("solvedNum").innerText = `solved: ${await (await fetch("/solved")).text()}`
         }
         async function submit() {
             await fetch('/solve', {
@@ -69,5 +70,6 @@
         <input type="text" id="solved" placeholder="solve the captcha above..">
         <button onclick="submit()">submit</button>
     </div>
+    <p id="solvedNum">solved: -</p>
 </body>
 </html>