一、class
1-1 构造函数中设置静态属性
class Point{static docLayer = null;constructor(option){//在构造函数中设置静态属性Point.docLayer = option.docLayer;}}
1-2 构造函数中的self和this
class Point{constructor(){console.log(this) //this指向当前实例的对象console.log(self) //self指向window}}
