限制输入个数

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

@@ -114,6 +114,7 @@ export default defineComponent({
                 v-model={this.code}
                 class={styles.field}
                 autocomplete="off"
+                maxlength={4}
               />
             </Col>
             <Col span="10" class={styles.img}>