流程控制语句

if判断
if(){

}else{

}

switch判断 条件要全等才行
switch(){
case value1:
statement;
break;

case value2:
     statement;
     break; 

default:
statement;

}

while 循环 条件不满足停止
const i = 10
while(i > 0){
console.log(i);
i--;
}

do-while 循环 不管条件满足与否 先执行一次再看条件
const i = 4
do{
console.log(i)
i--
}while(i > 5)

for循环 遍历数组
var arr = [100,80,70,45]
for(var i = 0; i < arr.lenght; i++){
console.log(arr[i]);
}

for in循环 遍历对象
var obj = {
name: "ruoyu"
age: 30
}

for(var key in obj){
console.log(obj[key])
}

break 强制退出循环体
continue 退出本次循环，执行下次循环