diff --git a/assets/js/signin.js b/assets/js/signin.js
index cf8e7933..3298f287 100644
--- a/assets/js/signin.js
+++ b/assets/js/signin.js
@@ -6,7 +6,7 @@
 (function () {
   'use strict';
 
-  if (!window.aksrtData || !window.AksrtRequest) {
+  if (!window.aksrtData) {
     return;
   }
 
@@ -132,14 +132,27 @@
 
         signinBusy = true;
         setButtonState('busy');
+        var captchaRequired = !!window.aksrtData.captchaSignin;
         var captcha = window.AKSRTCaptcha;
         var mount = captchaMount();
-        (captcha ? captcha.run('signin', mount) : Promise.resolve({})).then(function (payload) {
+
+        if (captchaRequired && (!captcha || !mount)) {
+          signinBusy = false;
+          notyf('人机验证未正确加载，请刷新页面后重试', 'danger');
+          setButtonState('idle');
+          return;
+        }
+        if (!captchaRequired) {
+          doSignin({});
+          return;
+        }
+
+        captcha.run('signin', mount).then(function (payload) {
           if (payload === null) throw new Error('已取消验证');
           doSignin(payload);
         }).catch(function (error) {
           signinBusy = false;
-          if (captcha) captcha.reset('signin', mount);
+          captcha.reset('signin', mount);
           notyf((error && error.message) || '人机验证加载中，请稍候再试', 'danger');
           setButtonState('idle');
         });
@@ -149,5 +162,15 @@
     refresh();
   }
 
-  jQuery(document).off('auto_fun.aksrt-signin').on('auto_fun.aksrt-signin', initSignin);
+  function boot() {
+    if (!window.AksrtRequest) return;
+    jQuery(document).off('auto_fun.aksrt-signin').on('auto_fun.aksrt-signin', initSignin);
+    initSignin();
+  }
+
+  if (typeof tbquire === 'function') {
+    tbquire(['main'], boot);
+  } else {
+    boot();
+  }
 })();
diff --git a/src/Core/ScriptsPart1c.php b/src/Core/ScriptsPart1c.php
index e51a01b1..586d5dd7 100644
--- a/src/Core/ScriptsPart1c.php
+++ b/src/Core/ScriptsPart1c.php
@@ -468,6 +468,7 @@ trait ScriptsPart1c {
             'ajaxUrl'               => admin_url('admin-ajax.php'),
             'nonce'                 => wp_create_nonce('aksrt_public_nonce'),
             'restNonce'             => wp_create_nonce('wp_rest'),
+            'captchaSignin'         => function_exists('aksrt_is_captcha_enabled_for') && aksrt_is_captcha_enabled_for('signin'),
             'visibilityNonce'       => wp_create_nonce('aksrt_visibility'),
             'siteUrl'               => home_url('/'),
             'themeUrl'              => AKSRT_URI,
diff --git a/tests/widget-system/captcha-runtime-harness.test.cjs b/tests/widget-system/captcha-runtime-harness.test.cjs
index 34243b0e..3fa0e673 100644
--- a/tests/widget-system/captcha-runtime-harness.test.cjs
+++ b/tests/widget-system/captcha-runtime-harness.test.cjs
@@ -8,6 +8,7 @@ const vm = require('node:vm');
 
 const root = path.resolve(__dirname, '..', '..');
 const runtime = fs.readFileSync(path.join(root, 'assets/js/captcha-front.js'), 'utf8');
+const signinSource = fs.readFileSync(path.join(root, 'assets/js/signin.js'), 'utf8');
 
 function createInput(name, value = '') {
   return { name, value, remove() {}, nodeType: 1 };
@@ -107,3 +108,59 @@ test('captcha run is single-flight until the owning business request resets', as
   api.reset('login', container);
   assert.equal(await second, null);
 });
+
+test('sign-in waits for main before binding and invokes the signin captcha', async () => {
+  const listeners = {};
+  const label = { textContent: '' };
+  const button = {
+    dataset: {},
+    disabled: false,
+    classList: { toggle() {} },
+    addEventListener(name, handler) { listeners[name] = handler; },
+    querySelector(selector) { return selector === '[data-signin-label]' ? label : null; },
+    getAttribute(name) {
+      if (name === 'data-signin-idle-label') return '签到';
+      if (name === 'data-signin-done-label') return '已签到';
+      return '';
+    },
+  };
+  const mount = { nodeType: 1 };
+  const document = {
+    querySelector(selector) { return selector === '[data-signin-captcha]' ? mount : null; },
+    querySelectorAll(selector) { return selector === '[data-signin-btn]' ? [button] : []; },
+  };
+  const jqueryApi = { off() { return this; }, on() { return this; } };
+  const jQuery = () => jqueryApi;
+  const window = { aksrtData: { captchaSignin: true } };
+  let mainReady;
+  let captchaCall = null;
+  const tbquire = (deps, callback) => {
+    assert.deepEqual(Array.from(deps), ['main']);
+    mainReady = callback;
+  };
+
+  vm.runInNewContext(signinSource, {
+    window, document, jQuery, tbquire, notyf() {}, Promise, JSON, Number,
+  });
+  assert.equal(listeners.click, undefined);
+  assert.equal(typeof mainReady, 'function');
+
+  window.AksrtRequest = {
+    request(endpoint) {
+      if (endpoint === '/signin/today') return Promise.resolve({ ok: true, status: 200, json: { enabled: true, signed: false, streak: 0, reward_if_signin: 1 } });
+      if (endpoint === '/signin') return Promise.resolve({ ok: true, status: 200, json: { message: '签到成功', balance: 1 } });
+      throw new Error('unexpected endpoint ' + endpoint);
+    },
+  };
+  window.AKSRTCaptcha = {
+    run(scene, scope) { captchaCall = { scene, scope }; return Promise.resolve({ aksrt_captcha_proof: 'proof' }); },
+    reset() {},
+  };
+
+  mainReady();
+  await new Promise((resolve) => setImmediate(resolve));
+  assert.equal(typeof listeners.click, 'function');
+  listeners.click({ preventDefault() {} });
+  await new Promise((resolve) => setImmediate(resolve));
+  assert.deepEqual(captchaCall, { scene: 'signin', scope: mount });
+});