语句

//语句
var i = 0;
if(i > 25) {
    console.log(1);
} else if(i<0) {
    console.log("小于0");
} else {
    console.log("between 0 and 25")
}

//do-while 语句
//while 条件是否满足，循环体内的语句都会执行
do {
    i++;
    console.log(i);
} while (i<2);
//while 语句 循环体的语句不一定会被执行
while(i<0){
    console.log(i);
}

//for 语句相当于while循环语句 while语句做不到的，for语句也做不到
for(var i =0; i<2; i++){
    console.log(i);
}

//for-in 语句 用来枚举对象的属性
for(var propName in window){
    console.log(propName);
}

//break 语句 跳出当前循环
for(var i = 1;i<10;i++){
   if(i%5==0){
       if(i%5==0) {
           console.log("5的倍数");
           break ;
       }
       console.log("break");
    }
}

//continue 语句 当条件不满足时才会执行continue后面的语句
for(var i = 1;i<10;i++){
        if(i%5==0) {
            continue ;
            console.log("5的倍数");
        }
}

//switch 语句 使用的是全等，不会发生类型转换
var num = 25;
switch (true) {
    case num < 0:
        alert("Less than 0.");
        break;
    case num >= 0 && num <= 10:
        alert("Between 0 and 10.");
        break;
    case num > 10 && num <= 20:
        alert("Between 10 and 20.");
        break;
    default:
        alert("More than 20.");
}

//函数内部修改的值，不会改变原有的引用

function setName(obj) {
    obj.name = "Naclosiz";
    obj = new Object();
    obj.name = "onjkj2"
    return obj;
}
var person = new Object();
var result = setName(person);
console.log(person.name);
console.log(result.name);

//instanceof  判断对象的类型
console.log(person instanceof Array);
console.log(Array.isArray(value));

//没有块级作用域
if(true) {
    var color ="blue"
}
console.log(color);
for(var i = 0; i<10 ;i++){}