修改图片验证码限制4位的问题

src/components/o-img-code/index.tsx

@@ -116,7 +116,12 @@ export default defineComponent({
           <p class={styles.codeTitle}>输入图形验证码</p>
           <Row>
             <Col span="14">
-              <Field placeholder="请输入验证码" v-model={this.code} class={styles.field} />
+              <Field
+                placeholder="请输入验证码"
+                v-model={this.code}
+                class={styles.field}
+                maxlength={4}
+              />
             </Col>
             <Col span="10" class={styles.img}>
               <VanImage src={this.identifyingCode} onClick={() => this.updateIdentifyingCode()}>