while

window.onload = function () {
while (true){
var i = 0;
var score = prompt('请输入小明的成绩');
if (score < 0 || score > 100){
alert('输入不合法，请重新输入');
continue;
}
else if(score == 100){
alert('奖励一辆BWM');
break;
}else if (score >= 80 || score <= 99){
alert('奖励一台iPhone15s');
break;
}else if(score >= 60 || score <= 79){
alert('奖励一本参考书');
break;
}else{
alert('什么奖励都没有');
break;
}
i++;
}
}