javascript中的隐藏的对象

Call
Apply
prototype
var person= function(){
};
person.prototype.say = function(){

}
//call
function class1(name){
  this.name = name
  this.showName (){
   alert(this.name);
  }
}
function class2(name){
  this.name = name
  class1.call(this);//把class1 赋给class2
}
var selection = document.getElementById('myselect');
var coloneselection = document.createElement('select');
coloneselection  = selection.cloneNode(true)//完全拷贝