一、构造函数在new实例时里面的代码就执行了一遍.
function task() {
console.log('ddd')
return this;
}
task.getName = function() {
this.a = 'cool'
console.log('kk')
}
task.prototype.getName = function () {
this.a = 'pu'
console.log(3);
};
var a=new task()
console.log("a:",a)
var a=new task().getName()
console.log("a:",a)