# IntersectionObserver.observe(string targetSelector, function callback)

> __小程序插件__：支持

> 相关文档: [获取界面上的节点信息](/miniprogram/dev/framework/view/selector.md)

## 功能描述

指定目标节点并开始监听相交状态变化情况

## 参数

### string targetSelector

选择器

### function callback

监听相交状态变化的回调函数

#### 参数

##### Object res


```json
[
  {
    "属性": "id",
    "类型": "string",
    "说明": "节点 ID"
  },
  {
    "属性": "dataset",
    "类型": "Record.<string, any>",
    "说明": "节点自定义数据属性"
  },
  {
    "属性": "intersectionRatio",
    "类型": "number",
    "说明": "相交比例"
  },
  {
    "属性": "intersectionRect",
    "类型": "Object",
    "说明": "相交区域的边界",
    "子项": [
      {
        "结构属性": "left",
        "类型": "number",
        "说明": "左边界"
      },
      {
        "结构属性": "right",
        "类型": "number",
        "说明": "右边界"
      },
      {
        "结构属性": "top",
        "类型": "number",
        "说明": "上边界"
      },
      {
        "结构属性": "bottom",
        "类型": "number",
        "说明": "下边界"
      },
      {
        "结构属性": "width",
        "类型": "number",
        "说明": "宽度"
      },
      {
        "结构属性": "height",
        "类型": "number",
        "说明": "高度"
      }
    ]
  },
  {
    "属性": "boundingClientRect",
    "类型": "Object",
    "说明": "目标边界",
    "子项": [
      {
        "结构属性": "left",
        "类型": "number",
        "说明": "左边界"
      },
      {
        "结构属性": "right",
        "类型": "number",
        "说明": "右边界"
      },
      {
        "结构属性": "top",
        "类型": "number",
        "说明": "上边界"
      },
      {
        "结构属性": "bottom",
        "类型": "number",
        "说明": "下边界"
      },
      {
        "结构属性": "width",
        "类型": "number",
        "说明": "宽度"
      },
      {
        "结构属性": "height",
        "类型": "number",
        "说明": "高度"
      }
    ]
  },
  {
    "属性": "relativeRect",
    "类型": "Object",
    "说明": "参照区域的边界",
    "子项": [
      {
        "结构属性": "left",
        "类型": "number",
        "说明": "左边界"
      },
      {
        "结构属性": "right",
        "类型": "number",
        "说明": "右边界"
      },
      {
        "结构属性": "top",
        "类型": "number",
        "说明": "上边界"
      },
      {
        "结构属性": "bottom",
        "类型": "number",
        "说明": "下边界"
      }
    ]
  },
  {
    "属性": "time",
    "类型": "number",
    "说明": "相交检测时的时间戳"
  }
]
```