javascript基础

1 　  　var Person = new Object();
2         Person.name = "js";
3         Person.age = 19;
4         alert(Person.name);
5         //如果对象不被销毁或者这个属性不被删除，这个属性将一直存在

1         var Num1 = 1;
2         var Num2 = Num1;
3         Num1 = 2;
4         alert("Num1" + Num1 + "\nNum2" + Num2);
5         //基本类型复制

1  　　　　var obj1 = new Object();
2         var obj2 = obj1;
3         obj1.name = "obj1";
4         obj2.name = "obj2";
5         alert("obj2.name" + obj2.name + "\nobj1.name" + obj1.name);
6         //引用类型复制

 1     var obj = new Object();
 2         obj.name = "obj1";
 3         function setName(obj) {
 4             obj.name = "after setName";
 5         }
 6         setName(obj);
 7         alert(obj.name);//after setName
 8 
 9         var obj2 = new Object();
10         obj2.name = "obj2";
11         function setName2(obj) {
12             obj = new Object();
13             obj.name = "this is new obj‘s Name";
14         }
15         alert(obj2.name);//obj2

     var ty1 = 1;//Number
        var ty2 = "ty2";//String
        var ty3 = false;//Boolean
        var ty4 = new Object();//Object
        var ty5 = null;//Object
        var ty6;//undefined
        alert(typeof ty1);
        alert(typeof ty2);
        alert(typeof ty3);
        alert(typeof ty4);
        alert(typeof ty5);
        alert(typeof ty6);

1   var arry = [1, 2, 3];
2         alert(arry instanceof Array);//true
3 
4         var person = new Object();
5         alert(Object instanceof Object);// true