作业

while循环
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++;
      }
  }

window.onload = function () {
      var i = 1000;
      var j = 0;
      while (true){
          i = i * 1.05;
          if (i >= 5000){
              break;
          }
       j++;
      }
   alert(j);
  }