while循环案例

        var into = prompt('你爱我吗?')
        while (into != '爱你') {
            into = prompt('你爱我吗?');
        }
        alert('我也爱你呀')

        var year = 1;
        while (year <= 100) {
            console.log('他' + year + '岁了')
            year++;
        }

do…while循环案例

    var i=1,sum=0;
        do{
            sum+=i;
            i++;
        }while(i<=100);
        console.log(sum)

        var life = 1;
        // do执行开始,while进行条件判定
        do {
            console.log("你" + life + "岁了!");
            life++;
        } while (life <= 99)