--- title: "一次性验证码字段" description: "以一个完整字段的形式，向用户索取发送给他的简短验证码：标签下方是格子，带有一行帮助文本和验证码错误时的文字；它们为辅助技术关联在一起，并作为一个控件参与表单。" url: "https://tanrei.chnotchy.com/zh-cn/components/one-time-code-field/" last_updated: 2026-10-23T21:17:12.000Z --- # 一次性验证码字段 > 以一个完整字段的形式，向用户索取发送给他的简短验证码：标签下方是格子，带有一行帮助文本和验证码错误时的文字；它们为辅助技术关联在一起，并作为一个控件参与表单。 ## 概览 只要产品要求用户回填它发出的简短验证码，就使用一次性验证码字段：登录、确认某个地址或电话号码、批准一笔付款。它对应的是最常见的情况，可以直接使用：一个标签、一排格子、一行说明验证码发到了哪里的文字，以及验证码错误时的文字。 **组成部分**是一个[字段](https://tanrei.chnotchy.com/zh-cn/components/field/)和一个[一次性验证码输入框](https://tanrei.chnotchy.com/zh-cn/components/one-time-code-input/)。字段是框架：标签、必填或选填标记、帮助文本和错误。一次性验证码输入框是控件：格子，以及用户在格子里做的一切。一次性验证码字段自己什么都不绘制，也没有令牌：它的每个属性都是这两者之一的属性，原样交给它们。 它的宽度与所在的位置相同，格子从它的起始边开始排。 在 Web 上它是 ``。其他平台尚未实现。 ### 用法 `value` 是到目前为止已输入的验证码；无论画出怎样的分组，其中都没有分隔符。四个事件是一次性验证码输入框自己的事件；监听到其中任何一个时，字段的 `value` 都已经是新的值。 **Web** ```html
``` **React** ```tsx import { OneTimeCodeField } from '@tanrei/react'; setCode(event.currentTarget.value)} onComplete={(event) => verify(event.detail.value)} /> ``` ### 下一层 用它的两个成员手写出来的同一个字段，画面是一样的，对辅助技术来说也是同一个文本框： ```html ``` 当你需要一次性验证码字段没有提供的排布方式时，就往下走一层： | 你需要 | 使用 | | --- | --- | | 标签、格子、帮助文本和错误 | 一次性验证码字段 | | 在框架里面、格子旁边放你自己的东西：重新发送验证码的控件、倒计时 | 一个[字段](https://tanrei.chnotchy.com/zh-cn/components/field/)，里面放一个[一次性验证码输入框](https://tanrei.chnotchy.com/zh-cn/components/one-time-code-input/)和你自己的元素 | | 只要格子，标签绘制在别处：对话框的标题、某个步骤的标题 | 单独使用的[一次性验证码输入框](https://tanrei.chnotchy.com/zh-cn/components/one-time-code-input/)，由它自己的 `label` 命名 | | 一个没有格子的输入框，用于长度未知的验证码 | 带 `autocomplete="one-time-code"` 的[文本字段](https://tanrei.chnotchy.com/zh-cn/components/text-field/) | 下到这一层之后，变的是各样东西写在哪里。`name` 和 `value` 写在一次性验证码输入框上，这时它就是表单面对的控件，它的事件也在它上面监听。`label`、`error` 和 `disabled` 仍然写在字段上，由字段转交给控件：不要设置输入框自己的这几项。 ## 规格 ### 各个成员提供什么 | 方面 | 来自字段 | 来自一次性验证码输入框 | | --- | --- | --- | | 属性 | `label`, `labelHidden`, `supportingText`, `errorText`, `error`, `disabled`, `required`, `optional`, `requiredMark`, `requiredText`, `optionalText` | `value`, `length`, `type`, `groupSize`, `mask`, `readOnly` | | 事件 | — | `input`, `change`, `complete`, `action` | | 插槽 | `label-icon` | — | | 令牌 | `comp.field.*` | `comp.one-time-code-input.*` | 一次性验证码输入框有它自己的 `label`、`error` 和 `disabled`。它们不是一次性验证码字段的属性：字段的 `label` 为控件命名，字段的 `error` 让格子进入错误状态，字段的 `disabled` 禁用格子。所以每一项你都只设置一次，设置在一次性验证码字段上，它的标签也随控件一起变化。 格子做什么，也就是键入、粘贴、方向键和分组，写在[一次性验证码输入框的页面](https://tanrei.chnotchy.com/zh-cn/components/one-time-code-input/)上。框架做什么，也就是必填标记、帮助文本、错误以及错误怎样朗读，写在[字段的页面](https://tanrei.chnotchy.com/zh-cn/components/field/)上。 ### 单独调整某一个字段 一次性验证码字段没有自己的令牌。它的框架读取字段的令牌，它的格子读取一次性验证码输入框的令牌，无论这些令牌设置在哪里。要改动某一个实例，就在它上面设置成员的令牌： ```html ``` - Category: Text inputs - Level: composed - Listing: default - Built from: Field, One-time-code input - Page: https://tanrei.chnotchy.com/components/one-time-code-field/ - Spec: https://github.com/chnotchy/tanrei/blob/main/specs/one-time-code-field.spec.json ### Availability | Design system | Has it | Notes | | --- | --- | --- | | Tanrei (`tanrei`) | Yes | — | | Cupertino (Apple HIG-inspired) (`cupertino`) | Yes | — | | M3 Expressive-like (Material 3 Expressive-inspired) (`m3-expressive-like`) | Yes | — | | M3-like (Material 3-inspired) (`m3-like`) | Yes | — | ### Platforms - Web: the element ``, registered by importing `@tanrei/web` (or only its own module, `@tanrei/web/components/one-time-code-field`). - React: `OneTimeCodeField` from `@tanrei/react`. | Platform | Name | Status | | --- | --- | --- | | Web | `tanrei-one-time-code-field` | lagging | | SwiftUI | `TanreiOneTimeCodeField` | planned | | Jetpack Compose | `TanreiOneTimeCodeField` | planned | | Flutter | `TanreiOneTimeCodeField` | planned | | React Native | `OneTimeCodeField` | planned | Names a platform gives in its own idiom: | Spec | Web | SwiftUI | Jetpack Compose | Flutter | React Native | | --- | --- | --- | --- | --- | --- | | `label` (prop) | `label` | `label` | `label` | `labelText` | `label` | | `labelHidden` (prop) | `labelHidden` | `labelsHidden` | `labelHidden` | `labelHidden` | `labelHidden` | | `supportingText` (prop) | `supportingText` | `supportingText` | `supportingText` | `helperText` | `supportingText` | | `error` (prop) | `error` | `error` | `isError` | `isError` | `error` | | `disabled` (prop) | `disabled` | `disabled` | `enabled` | `enabled` | `disabled` | | `required` (prop) | `required` | `isRequired` | `required` | `required` | `required` | | `optional` (prop) | `optional` | `isOptional` | `optional` | `optional` | `optional` | | `value` (prop) | `value` | `code` | `value` | `controller` | `value` | | `mask` (prop) | `mask` | `isMasked` | `masked` | `obscureText` | `secureTextEntry` | | `input` (event) | `input` | `code` | `onValueChange` | `onChanged` | `onChangeText` | | `change` (event) | `change` | `onCommit` | `onCommit` | `onCommit` | `onEndEditing` | | `complete` (event) | `complete` | `onComplete` | `onComplete` | `onCompleted` | `onComplete` | | `action` (event) | `action` | `onSubmit` | `keyboardActions` | `onSubmitted` | `onSubmitEditing` | Statuses: `planned` — In the inventory. Nothing shippable exists yet. `lagging` — An implementation of an earlier spec exists; it has not caught up with the current one. `alpha` — Implemented with tests. The API may still change. `beta` — Feature complete and at parity. Only fixes are expected. `stable` — Covered by semantic versioning. `deprecated` — Still shipped; scheduled for removal. ### Anatomy - `field`: The frame: a Field, whole — its label row with the label glyph and the requirement mark, and its supporting row, where the error text stands in the help's place or below it (FLD-7). Drawn by the Field from the Field's tokens (FLD-1 to FLD-9). - `one-time-code-input`: The frame's one control: a One-time-code input, whole — its cells, its characters, its caret and its group marks. Drawn by the One-time-code input from its own tokens (OTC-1 to OTC-3, OTC-15). ### Props | Prop | Type | Default | Web attribute | Description | | --- | --- | --- | --- | --- | | `label` | `string` | `""` | `label` | Names the control, visibly and to assistive technology. Required, unless the control names itself (a checkbox or a switch with its own label): then leave it empty and the field adds only help and an error. (From Field: Always given: the control of a one-time-code field never names itself, so the case of an empty label does not arise.) | | `labelHidden` | `boolean` | `false` | `label-hidden` | Does not draw the label, which stays the accessible name. For a control whose visible label is elsewhere (a table column, a toolbar). (From Field.) | | `supportingText` | `string` | `""` | `supporting-text` | Help shown below the control and given to assistive technology as the control's description. While the field is in error it gives way to errorText, unless the design system keeps both (comp.field.error-text.placement append). (From Field.) | | `errorText` | `string` | `""` | `error-text` | Shown while error is true, in supportingText's place — or below it, which then stays, where the design system's comp.field.error-text.placement is append: what is wrong and how to put it right, in words. (From Field.) | | `error` | `boolean` | `false` | `error` | Puts the field in the error condition: the error text is drawn, the control is exposed as invalid and, where it has an error condition of its own, drawn in it. What a value means is the product's to validate; the field never sets this itself. (From Field: The one error of the one-time-code field: the Field passes it to the control (FLD-8, OTC-17), whose own error is not a prop here.) | | `disabled` | `boolean` | `false` | `disabled` | Disables the control and draws the frame as disabled. Disable a framed control here, not on the control, so that its label follows. (From Field: The one disabled of the one-time-code field: the Field passes it to the control (FLD-14, OTC-20), whose own disabled is not a prop here.) | | `required` | `boolean` | `false` | `required` | What the form asks of the control: true exposes it as required and draws the required mark beside the label. It never validates: a missing answer is the product's to report with error. (From Field.) | | `optional` | `boolean` | `false` | `optional` | Draws the optional tag after the label and adds optionalText to the control's description, because assistive technology has no state for it. Ignored while required is true: a control is never both. (From Field.) | | `requiredMark` | `enum`: `auto`, `tag`, `asterisk`, `none` | `"auto"` | `required-mark` | How this control shows that it is required: tag is a small filled Tag with requiredText, asterisk is "*" after the label, none draws nothing and keeps the semantics. Auto takes comp.field.requirement.mark, which follows sys.behavior.requirement-mark, the system's one answer. Ignored unless required is true. (From Field.) | | `requiredText` | `string` | `""` | `required-text` | The text of the required tag, in the product's language ("Required", "必須"). The product's: Tanrei has no word for it. Empty reads the product's words; with neither, FLD-24 says what is drawn. (From Field.) | | `optionalText` | `string` | `""` | `optional-text` | The text of the optional tag, in the product's language ("Optional", "任意"); also read to assistive technology as part of the description. The product's: Tanrei has no word for it. Empty reads the product's words. (From Field.) | | `value` | `string` | `""` | `value` | The code entered so far: at most length characters, digits or, for alphanumeric, digits and upper-case letters, with no separator. One string, whatever the cells and groups drawn. (From One-time-code input.) | | `length` | `number` | `6` | `length` | How many characters the code has, and so how many cells are drawn. A whole number of 1 or more. (From One-time-code input.) | | `type` | `enum`: `numeric`, `alphanumeric` | `"numeric"` | `type` | What a cell takes: numeric is the digits 0 to 9, with a numeric keypad; alphanumeric is digits and the letters A to Z, held in upper case, with a general keyboard. (From One-time-code input.) | | `groupSize` | `number` | `0` | `group-size` | Draws the cells in groups of this many, counted from the first, with a mark between two groups (3 for a six-character code written "123 456"). 0 draws one group. It changes the drawing only: the value has no separator. (From One-time-code input.) | | `mask` | `boolean` | `false` | `mask` | Draws the platform's obscuring mark in each filled cell in place of its character, and exposes the field as protected. For a screen other people can see; a code that is used once and expires rarely needs it. (From One-time-code input.) | | `readOnly` | `boolean` | `false` | `readonly` | Keeps the field focusable and its value readable, and lets nothing change it: for the moment a complete code is being checked, when taking focus away would lose the place of a person who must then correct it. (From One-time-code input.) | ### Events | Event | Description | | --- | --- | | `input` | The person changed the value; carries the new value. Emitted for every change, not when the product sets value. (From One-time-code input.) | | `change` | The person committed a changed value (focus left the field, or the action key was pressed); carries the value. (From One-time-code input.) | | `complete` | A change by the person left the value length characters long; carries the value. Emitted after input, once for that change. The field does nothing else: checking the code is the product's. (From One-time-code input.) | | `action` | The person pressed the keyboard's action key (Enter, Return, Done). (From One-time-code input.) | ### Slots | Slot | Description | | --- | --- | | `label-icon` | A glyph before the label. (From Field.) | ### States `enabled`, `disabled`, `hovered`, `focused`, `error` ### Accessibility - Role: `textbox` - Labeling: One text box, the One-time-code input's (OTC-2); the frame has no role. Its accessible name is label, drawn or not (labelHidden), and its description is the supporting text with, in error, the error text after it, with optionalText while optional is true (FLD-10, FLD-11, OTC-22). It is exposed as invalid while error is true, required while required is true, disabled while disabled is true, read-only while readOnly is true, and as a protected text entry while mask is true. The label's drawn text, the requirement mark, the cells, the caret and the group marks are not exposed a second time (FLD-11, OTC-2). - Minimum target size: yes | Keys | Action | | --- | --- | | Tab / Shift+Tab | Moves focus to the control and on from it: the one-time-code field is one stop, its control's, and adds none (OTF-5). | | Every other key | The One-time-code input's own, as its spec's keyboard table says (OTC-6, OTC-8 to OTC-11, OTC-13). The one-time-code field handles no key. | - What the one-time-code field adds to its members is their being one thing: one tag or one call, one set of props, one value and one entry in a form (OTF-2 to OTF-4). The tie between the two — the name, the description, required, invalid, disabled — is not the one-time-code field's: it is what a Field gives any control it frames, and it runs here exactly as it runs in a product's own Field. - One level down: a Field with a One-time-code input in it, written by the product, is the same picture and the same text box, and the Field's fixtures code-supporting, code-error, code-disabled and code-required-rtl are this component's twins. A product drops to it for an arrangement the one-time-code field does not offer: something of its own inside the frame beside the cells (a resend control, a countdown), or the One-time-code input alone under a dialog's headline, named by its own label. - The members' notes hold as written and are not repeated: errors are words (the Field's); nothing happens by itself when the code is complete, and paste and the platform's autofill are never blocked (the One-time-code input's). - The hit area is the control's (OTC-25); the label widens where a press can land without widening what a press does (FLD-12). - Not pressable: a press focuses the control and is not an action (OTC-25), so BTN-8, BTN-9 and BTN-10 are not copied. - How a state looks is a value decision of the active design system; components read the state's tokens and never compute the effect themselves. ### Behaviour Requirements in EARS form, each with its stable id. - **OTF-1** THE one-time-code field SHALL be a Field whose one control is a One-time-code input, and SHALL draw nothing of its own: every row, text, mark, cell and line it shows is drawn by one of the two, from that component's own tokens, as FLD-1 to FLD-8 and OTC-1 to OTC-3, OTC-7 and OTC-15 to OTC-17 say. THE one-time-code field SHALL have no token, no size and no gap of its own: the Field places the control and gives it its width (FLD-1), and the One-time-code input lays its row out in that width (OTC-1, OTC-23). What it shows SHALL be the picture a product gets by placing that One-time-code input in that Field by hand with the same values, and what assistive technology is told SHALL be the same name, description and states (FLD-10, FLD-11, OTC-22). - **OTF-2** THE one-time-code field SHALL give each of its props, unchanged, to the member it is from and SHALL hold no state between the two: label, labelHidden, supportingText, errorText, error, disabled, required, optional, requiredMark, requiredText and optionalText are the Field's; value, length, type, groupSize, mask and readOnly are the One-time-code input's. A value a member does not know SHALL be passed on as given and answered by that member (FLD-22, OTC-19). THE one-time-code field SHALL never set the One-time-code input's own label, error or disabled: the Field's label names the control (FLD-10, OTC-22), the Field's error puts it in its error condition (FLD-8, OTC-17) and the Field's disabled disables it (FLD-14, OTC-20), so that each is said once, in the place where the label follows. - **OTF-3** THE one-time-code field SHALL hold one value, the One-time-code input's. WHEN the person changes it THE one-time-code field's value SHALL be the new one before any event is reported, and THE one-time-code field SHALL report input, change, complete and action as the One-time-code input emits them — the same events, carrying the same value, in the same order and as often (OTC-13, OTC-14) — as its own, adding none and holding none back. WHEN the product sets value THE one-time-code field SHALL show it as OTC-18 says and SHALL report no event. - **OTF-4** WHERE the platform has forms (the web) THE one-time-code field SHALL be the one control the form meets, and what OTC-29 says of a One-time-code input SHALL hold of the one-time-code field as a whole: it takes name; it submits the code alone, an empty string WHILE it holds none, and nothing WHILE disabled (OTC-20); it is restored on navigation and resets to the value it was first given; and it reports a missing value WHILE required is true and the value is empty, and nothing for a code shorter than length. Its members SHALL add no entry of their own to the form, and the action key SHALL submit the form the one-time-code field belongs to as OTC-13 says, unless action was cancelled. - **OTF-5** THE one-time-code field SHALL be one stop in the focus order, its control's (FLD-12, OTC-2). WHEN the product moves focus to the one-time-code field THE one-time-code field SHALL pass it to the control, whose active cell is then the one OTC-5 names. A press on the label row SHALL move focus to the control and a press on the supporting row SHALL do nothing (FLD-12); THE one-time-code field SHALL take focus for no other press, SHALL add no key, and SHALL draw no focus indicator of its own: the frame's focused tokens and the active cell's focused line are the members' (FLD-13, OTC-7). - **OTF-6** THE one-time-code field SHALL hold exactly one control and SHALL take no other from the product: it has no place for a child but the Field's label glyph (FLD-3, FLD-20), so that the cases of FLD-15 — no control, several controls — and of FLD-23 — a control replaced by another — never arise in it. IF the one-time-code field is placed in a Field THEN THE one-time-code field SHALL be drawn as it is and reported in debug builds as a field placed in a Field (FLD-15); WHERE it is placed in a field group THE one-time-code field SHALL follow the group's disabled as a Field does (FGR-14) and SHALL take nothing else from the group. - **OTF-7** THE one-time-code field SHALL have no words of its own: every word it shows or says is a prop of the Field's, read as FLD-24 says — the instance's, else the product's words of the same name — and the One-time-code input has none (OTC-30). THE one-time-code field SHALL read no key of the product's words itself. - **OTF-8** THE one-time-code field SHALL add nothing to how its members answer the place they are used in: the layout direction (FLD-18 to FLD-21; OTC-27 and OTC-28, by which the cells stay a left-to-right run and stand at the start edge, under the label), enlarged text (FLD-16, OTC-23, OTC-24), a person's own forced colors (FLD-17, OTC-26) and the caret's reduced motion are each member's own answer. THE one-time-code field SHALL have no direction, size, color or motion setting of its own, and SHALL never be wider than its layout gives it. - **OTF-9** WHERE the platform has ARIA attributes (the web), WHEN the product sets an aria- attribute on the host, by the attribute or by the ARIA property that reflects it, THE one-time-code field SHALL move it to the data-aria- attribute of the same name, so that the host is no second node with its name, description or state, and SHALL expose it on the element that carries its role — an id reference by the elements it names in the host's tree or a tree around it, an error message as part of the description while the one-time-code field is invalid — except those the one-time-code field owns (aria-label, aria-labelledby, aria-disabled), which it SHALL move and not expose: its name is label (OTF-1). WHEN the product removes the aria- attribute or its data-aria- twin, or sets the ARIA property that reflects it (ariaLabel, ariaDescribedByElements…) to null, THE one-time-code field SHALL take it off that element. WHEN the product sets an aria- attribute the one-time-code field owns THE one-time-code field SHALL report it in debug builds. ### Tokens As written in the token documents (DTCG): an alias in braces names the token it takes its value from, which each design system resolves. On the web each token is a CSS custom property: `--tanrei` and the name after `tanrei`, joined by hyphens (`tanrei.comp.field.…` → `--tanrei-comp-field-…`). #### `tanrei.comp.field` | Token | Type | Value | | --- | --- | --- | | `comp.field.label.typescale` | `typography` | `{tanrei.sys.typescale.label}` | | `comp.field.label.gap` | `dimension` | `{tanrei.sys.space.space100}` | | `comp.field.label-icon.size` | `dimension` | `{tanrei.sys.icon.small}` | | `comp.field.label-icon.gap` | `dimension` | `{tanrei.sys.space.space100}` | | `comp.field.requirement.mark` | `number` | `{tanrei.sys.behavior.requirement-mark}` | | `comp.field.requirement.gap` | `dimension` | `{tanrei.sys.space.space100}` | | `comp.field.requirement.asterisk-gap` | `dimension` | `{tanrei.sys.space.space25}` | | `comp.field.supporting-text.typescale` | `typography` | `{tanrei.sys.typescale.label-small}` | | `comp.field.supporting-text.gap` | `dimension` | `{tanrei.sys.space.space50}` | | `comp.field.counter.gap` | `dimension` | `{tanrei.sys.space.space200}` | | `comp.field.motion.state-duration` | `duration` | `{tanrei.sys.motion.role.state.default}` | | `comp.field.motion.state-easing` | `cubicBezier` | `{tanrei.sys.motion.easing.state}` | | `comp.field.standard.label.color` | `color` | `{tanrei.sys.color.on-surface}` | | `comp.field.standard.label-icon.color` | `color` | `{tanrei.sys.color.on-surface-variant}` | | `comp.field.standard.supporting-text.color` | `color` | `{tanrei.sys.color.on-surface-variant}` | | `comp.field.standard.counter.color` | `color` | `{tanrei.sys.color.on-surface-variant}` | | `comp.field.standard.required-asterisk.color` | `color` | `{tanrei.sys.color.primary}` | | `comp.field.standard.error.label.color` | `color` | `{tanrei.sys.color.on-surface}` | | `comp.field.standard.error.label-icon.color` | `color` | `{tanrei.sys.color.on-surface-variant}` | | `comp.field.standard.error.supporting-text.color` | `color` | `{tanrei.sys.color.on-surface-variant}` | | `comp.field.standard.error.counter.color` | `color` | `{tanrei.sys.color.on-surface-variant}` | | `comp.field.standard.error.required-asterisk.color` | `color` | `{tanrei.sys.color.primary}` | | `comp.field.standard.error.value-text.color` | `color` | `{tanrei.sys.color.on-surface-variant}` | | `comp.field.standard.value-text.color` | `color` | `{tanrei.sys.color.on-surface-variant}` | | `comp.field.standard.error-text.color` | `color` | `{tanrei.sys.color.error}` | | `comp.field.value-text.typescale` | `typography` | `{tanrei.sys.typescale.label}` | | `comp.field.value-text.gap` | `dimension` | `{tanrei.sys.space.space200}` | | `comp.field.error-text.gap` | `dimension` | `{tanrei.sys.space.space50}` | | `comp.field.error-text.placement` | `number` | `0` | Per-state tokens, valued by the design system's pattern rules (not written by hand): - `comp.field...` for the variants `standard`, the states `focused`, `disabled` and the properties `label.color`, `label-icon.color`, `supporting-text.color`, `required-asterisk.color`, `error.label.color`, `error.label-icon.color`, `error.supporting-text.color`, `error.required-asterisk.color`, `counter.color`, `error.counter.color`, `value-text.color`, `error.value-text.color`, `error-text.color`. ### Web 上绘制方式的不同之处 - 这个元素的 shadow root 里有一个 ``，其中放着一个 ``，此外什么都没有。导入这个元素，两个成员也随之完成定义。 - 这个元素是与表单关联的元素。它接受 `name` 和 `form`；提交的只有验证码，禁用时什么都不提交；重置为 `value` 属性（attribute）的值；跟随被禁用的 `
`；设置了 `required` 而它为空时，报告缺少值。它的两个成员不向表单添加任何条目。在格子里按 Enter 会按下元素所在表单的默认按钮；取消 `action` 可以阻止这一点。 - `input`、`change`、`complete` 和 `action` 是一次性验证码输入框的 CustomEvent，带有 `detail.value`。它们的 target 是这个元素，在每个监听器里，`event.target.value` 都是验证码。 - 部件：`field` 和 `one-time-code-input` 是两个成员。成员自己的部件在这里的名称与下一层相同：`label`、`label-icon`、`requirement-label`、`supporting-text`；`input`、`cell`、`character`、`caret`、`separator`。 - 这个元素本身不能获得焦点：`focus()` 会把焦点交给格子，页面自己的 `