for-of循环

/*
 1. 遍历数组
 2. 遍历Set
 3. 遍历Map
 4. 遍历字符串
 5. 遍历伪数组
 6. 可迭代的对象
 */
var arr = [2,3,4];
for(let ele of arr) {
    console.log(ele);
}

var set = new Set([3, 5, 7, 5]);
for(let item of set) {
    console.log(item);
}

var map = new Map([["name", 'www'], ["age" , 10]]);
for(let [n,a] of map) {
    console.log(n, a);
}

for(let s of "abcde") {
    console.log(s);
}

var buttons = document.getElementsByTagName('button');
for(let button of buttons) {
    console.log(button.innerHTML);
}