### Initialize Sensors Data Web JS SDK and A/B Testing Plugin

Source: https://context7.com/sensorsdata/abtesting-sdk-web/llms.txt

Includes importing the necessary SDKs and plugins, initializing the main JS SDK, and then registering and initializing the A/B Testing plugin with various configuration options for experiments.

```html
<!-- 1. 引入神策 Web JS SDK -->
<script src="https://cdn.example.com/sensorsdata.min.js"></script>
<!-- 2. 引入 A/B Testing 插件（UMD 格式） -->
<script src="./abtest.min.js"></script>

<script>
// 初始化神策 Web JS SDK
var sa = sensorsDataAnalytic201505;
sa.init({
  server_url: 'https://your-server.sensorsdata.cn/sa?project=default',
  is_track_single_page: true,
  use_client_time: true,
  send_type: 'beacon'
});

// 注册 A/B Testing 插件
sa.use('SensorsABTest', window.SensorsDataWebJSSDKPlugin.SensorsABTest);

// 初始化 A/B Testing 插件
var abtest = window.SensorsDataWebJSSDKPlugin.SensorsABTest;
abtest.init(sa, {
  // 代码试验：传入分流服务地址（必须包含 project-key 参数）
  url: 'https://abtesting.example.com/api/v2/abtest/online/results?project-key=YOUR_PROJECT_KEY',
  // 请求超时时间（毫秒），默认 3000
  timeout_milliseconds: 3000,
  // 本地缓存更新间隔（毫秒），默认 600000（10 分钟）
  update_interval: 600000,
  // 是否上报 bridge 状态属性，默认 true
  collect_bridge_status: true,
  // 是否加密本地缓存，默认 false
  encrypt_cookie: false,

  // 多链接试验配置，false 表示关闭
  multilink: {
    timeout: 500,          // 等待分流结果的最大时间（ms）
    use_mask: true,        // 是否显示白屏遮罩防止页面闪烁
    pass_params: true,     // 是否将原始 URL 参数传递到跳转目标
    control_link_search: 'default',     // 对照组 URL 参数处理策略
    experiment_link_search: 'default'   // 试验组 URL 参数处理策略
  },

  // 可视化试验配置，false 表示关闭
  visualize: {
    enable_visualize: true,
    timeout: 500,
    use_mask: true
  }
});
</script>
```

--------------------------------

### Initialize Multilink Experiment

Source: https://context7.com/sensorsdata/abtesting-sdk-web/llms.txt

Initializes the A/B Testing SDK with multilink experiment configurations. Supports custom redirect behavior via `onRedirect` hook. Ensure the SDK is loaded before the `init` call.

```javascript
abtest.init(sa, {
  url: 'https://abtesting.example.com/api/v2/abtest/online/results?project-key=YOUR_KEY',
  multilink: {
    timeout: 500,
    use_mask: true,
    pass_params: true,
    // 自定义跳转行为（可选，默认直接修改 location.href）
    onRedirect: function (targetUrl) {
      console.log('即将跳转至试验组 URL：', targetUrl);
      // 可在此处加入埋点或动画后再跳转
      setTimeout(function () {
        location.href = targetUrl;
      }, 100);
    }
  },
  visualize: false
});

// URL 参数说明：
// 对照组：https://example.com/product?id=123
// 试验组：https://example.com/product-v2?id=123
// 命中后 SDK 自动处理跳转，pass_params=true 时保留 ?id=123 参数
```

--------------------------------

### Initialize Visual A/B Test

Source: https://context7.com/sensorsdata/abtesting-sdk-web/llms.txt

Initializes the A/B Testing SDK to enable visual A/B tests. Requires `enable_visualize: true` to activate. The SDK uses `MutationObserver` to apply changes and supports SPA route transitions.

```javascript
abtest.init(sa, {
  url: 'https://abtesting.example.com/api/v2/abtest/online/results?project-key=YOUR_KEY',
  multilink: false,
  visualize: {
    // 必须显式设置为 true 才能开启可视化试验
    enable_visualize: true,
    // 遮罩超时时间（ms），超时后自动移除遮罩恢复页面
    timeout: 500,
    // 是否开启遮罩层防止闪烁
    use_mask: true,
    // 自定义可视化试验 vabtest.min.js 的加载地址（可选）
    vabtest_url: 'https://static.sensorsdata.cn/sdk/plugin/vabtest/0.1.4/vabtest.min.js'
  }
});

// 可视化试验配置示例（在神策平台配置，SDK 自动执行）：
// {
//   "experiment_type": "VISUAL",
//   "control_link": "https://example.com/home",
//   "link_match_type": "FUZZY",
//   "experiment_value": [
//     {
//       "selector": "body > div:nth-of-type(1) > h1:nth-of-type(1)",
//       "tagName": "h1",
//       "props": {
//         "text": "新版标题文案",
//         "attributes": {
//           "style": { "color": "#ff4d4f", "fontSize": "24px" }
//         }
//       }
//     }
//   ]
// }
```

--------------------------------

### SDK Initialization

Source: https://context7.com/sensorsdata/abtesting-sdk-web/llms.txt

Initializes the A/B Testing plugin after the Sensors Web JS SDK is ready. It requires the SDK instance and configuration parameters, including settings for multi-link and visual experiments.

```APIDOC
## SDK Initialization `init(sd, para)`

### Description
Initializes the A/B Testing plugin after the Sensors Web JS SDK is ready. It requires the SDK instance and configuration parameters, including settings for multi-link and visual experiments.

### Parameters
- **sd** (object) - The initialized Sensors Web JS SDK instance.
- **para** (object) - Configuration object for the A/B Testing plugin.
  - **url** (string) - The URL for the A/B Testing service (must include project-key).
  - **timeout_milliseconds** (number) - Request timeout in milliseconds (default: 3000).
  - **update_interval** (number) - Local cache update interval in milliseconds (default: 600000).
  - **collect_bridge_status** (boolean) - Whether to report bridge status properties (default: true).
  - **encrypt_cookie** (boolean) - Whether to encrypt local cache (default: false).
  - **multilink** (object, optional) - Configuration for multi-link experiments.
    - **timeout** (number) - Maximum time to wait for split test results (ms).
    - **use_mask** (boolean) - Whether to display a white screen mask to prevent page flicker.
    - **pass_params** (boolean) - Whether to pass original URL parameters to the target link.
    - **control_link_search** (string) - Control group URL parameter processing strategy.
    - **experiment_link_search** (string) - Experiment group URL parameter processing strategy.
  - **visualize** (object, optional) - Configuration for visual experiments.
    - **enable_visualize** (boolean) - Enable visual experiments.
    - **timeout** (number) - Timeout for visual experiment requests (ms).
    - **use_mask** (boolean) - Whether to display a white screen mask.
```

--------------------------------

### fastFetchABTest

Source: https://context7.com/sensorsdata/abtesting-sdk-web/llms.txt

Prioritizes reading from local cache, and if the cache is missed, it requests the server. This method offers a balance between performance and real-time data, making it the most commonly used for code experiments.

```APIDOC
## `fastFetchABTest(para)`

### Description
Prioritizes reading from local cache (localStorage), and if the cache is missed, it requests the server. This method offers a balance between performance and real-time data, making it the most commonly used for code experiments.

### Parameters
- **para** (object)
  - **param_name** (string) - The name of the experiment parameter.
  - **value_type** (string) - The expected data type of the returned value ('String', 'Number', 'Boolean', 'Object').
  - **default_value** (any) - The default value if the experiment is not hit or the request fails. Must match `value_type`.
  - **timeout_milliseconds** (number, optional) - Request timeout in milliseconds.
  - **properties** (object, optional) - Custom properties for fine-grained user segmentation.
  - **callback** (function) - Required. A callback function that receives the experiment result.
```

--------------------------------

### Initialize for App H5 JSBridge Mode

Source: https://context7.com/sensorsdata/abtesting-sdk-web/llms.txt

Initializes the A/B Testing SDK for App H5 environments. The SDK automatically detects and uses JSBridge if available, falling back to HTTP mode otherwise. `collect_bridge_status` enables reporting of bridge status in events.

```javascript
// H5 场景下 init 配置与 Web 一致，SDK 自动切换通道
abtest.init(sa, {
  // H5 场景下 url 字段非必须（Bridge 模式不需要），但保留也不影响
  url: 'https://abtesting.example.com/api/v2/abtest/online/results?project-key=YOUR_KEY',
  timeout_milliseconds: 3000,
  collect_bridge_status: true,  // 开启后触发事件携带 $sdk_bridge_status
  multilink: false,
  visualize: false
});

// SDK 内部 bridgeState 可能值：
// 'ab_bridge_ok'        — Bridge 连接成功，通过 App 获取分流
// 'ab_no_host_bridge'   — 无 App Bridge，使用 HTTP 模式（Web 环境）
// 'ab_no_abtest_bridge' — App Bridge 存在但不支持 A/B 模块

// 调用方式与 Web 端完全一致
abtest.fastFetchABTest({
  param_name: 'app_h5_banner',
  value_type: 'String',
  default_value: 'default_banner',
  callback: function (value) {
    renderBanner(value);
  }
});
```

--------------------------------

### Fetch AB Test Variable with Cache Priority

Source: https://context7.com/sensorsdata/abtesting-sdk-web/llms.txt

The `fastFetchABTest` interface is recommended for most code experiment scenarios as it prioritizes local cache lookup before making a network request. It balances performance and real-time needs.

```javascript
abtest.fastFetchABTest({
  param_name: 'checkout_button_color',
  value_type: 'String',
  default_value: '#1890ff',
  timeout_milliseconds: 1500,
  // 用于精细化分组的自定义属性
  properties: {
    is_new_user: true
  },
  callback: function (color) {
    var btn = document.getElementById('checkout-btn');
    if (btn) {
      btn.style.backgroundColor = color;
      console.log('按钮颜色试验值：', color);
    }
  }
});

// Object 类型示例
abtest.fastFetchABTest({
  param_name: 'recommend_algo_config',
  value_type: 'Object',
  default_value: { strategy: 'default', limit: 10 },
  callback: function (config) {
    console.log('推荐算法配置：', config.strategy, '条目数量：', config.limit);
    loadRecommendations(config);
  }
});
```

--------------------------------

### asyncFetchABTest

Source: https://context7.com/sensorsdata/abtesting-sdk-web/llms.txt

Fetches experiment variables from the server in real-time with each call. This method is suitable for scenarios requiring strong real-time data.

```APIDOC
## `asyncFetchABTest(para)`

### Description
Fetches experiment variables from the server in real-time with each call. This method is suitable for scenarios requiring strong real-time data. The `callback` function receives the experiment result.

### Parameters
- **para** (object)
  - **param_name** (string) - The name of the experiment parameter configured on the Sensors A/B Testing platform.
  - **value_type** (string) - The expected data type of the returned value. Supported types: 'String', 'Number', 'Boolean', 'Object'.
  - **default_value** (any) - The default value to use if the experiment is not hit or the request fails. Must match `value_type`.
  - **timeout_milliseconds** (number, optional) - Request timeout in milliseconds. If not set, the global configuration is used.
  - **custom_properties** (object, optional) - Custom properties for user segmentation.
  - **callback** (function) - Required. A callback function that receives the experiment result.
```

--------------------------------

### Fetch AB Test Variable from Cache Only (Synchronous)

Source: https://context7.com/sensorsdata/abtesting-sdk-web/llms.txt

Use `fetchCacheABTest` for synchronous retrieval of experiment variables directly from memory or localStorage cache. This method does not initiate any network requests and is suitable for critical rendering paths.

```javascript
// 同步读取缓存中的试验变量
var fontSize = abtest.fetchCacheABTest({
  param_name: 'article_font_size',
  value_type: 'Number',
  default_value: 14
});

// 直接使用返回值（无 callback）
console.log('当前字号：', fontSize);
document.body.style.fontSize = fontSize + 'px';

// Boolean 类型示例
var showNewFeature = abtest.fetchCacheABTest({
  param_name: 'enable_new_editor',
  value_type: 'Boolean',
  default_value: false
});

if (showNewFeature) {
  loadNewEditor();
} else {
  loadLegacyEditor();
}
```

--------------------------------

### Fetch AB Test Variable with Real-time Request

Source: https://context7.com/sensorsdata/abtesting-sdk-web/llms.txt

Use `asyncFetchABTest` for scenarios requiring strong real-time data. It makes a network request on each call and returns results via a callback. Ensure `default_value` matches `value_type`.

```javascript
abtest.asyncFetchABTest({
  // 试验参数名（在神策 A/B Testing 平台配置）
  param_name: 'home_banner_title',
  // 期望返回的值类型
  value_type: 'String',
  // 若未命中试验或请求失败时的默认值
  default_value: '默认标题',
  // 请求超时时间（ms），可选，未设置则使用全局配置
  timeout_milliseconds: 2000,
  // 自定义属性（用于定向人群分组），可选
  custom_properties: {
    user_level: 'vip',
    city: 'beijing'
  },
  // 必填：接收试验结果的回调
  callback: function (result) {
    if (typeof result === 'string') {
      document.getElementById('banner-title').innerText = result;
      console.log('命中试验，变量值：', result);
    } else {
      console.log('未命中试验，使用默认值：', result);
    }
  }
});
```

--------------------------------

### fetchCacheABTest

Source: https://context7.com/sensorsdata/abtesting-sdk-web/llms.txt

Synchronously reads only from local cache (memory/localStorage) without making any network requests. This is suitable for retrieving cached experiment variables critical for page rendering.

```APIDOC
## `fetchCacheABTest(para)`

### Description
Synchronously reads only from local cache (memory/localStorage) without making any network requests. This is suitable for retrieving cached experiment variables critical for page rendering.

### Parameters
- **para** (object)
  - **param_name** (string) - The name of the experiment parameter.
  - **value_type** (string) - The expected data type of the returned value ('String', 'Number', 'Boolean', 'Object').
  - **default_value** (any) - The default value if the experiment is not found in cache. Must match `value_type`.

### Returns
- (any) The experiment variable value from the cache, or the `default_value` if not found.
```

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