bug fixes

src/pages/login/codeLogin.vue

@@ -2,7 +2,13 @@
   <div class="code-login">
     <van-form class="login-form" ref="form" v-on="$listeners">
       <van-field v-model="ruleForm.account" name="account" label="手机号" placeholder="请输入手机号" />
-      <van-field v-model="ruleForm.password" name="password" label="验证码" placeholder="请输入验证码">
+      <van-field
+        v-model="ruleForm.password"
+        :maxlength="4"
+        name="password"
+        label="验证码"
+        placeholder="请输入验证码"
+      >
         <template slot="button">
           <countdown-button @click.native="onSendCode" ref="countdown"></countdown-button>
         </template>