<script type="text/javascript">
    var i=iSum=0;
    while(i <= 100){
        iSum += i;
        i++;
     };
    document.write(iSum+"<br>"); //求100内数字相加和
     </script>
 <p>点击下面的按钮，只要 i 小于 5 就一直循环代码块。</p>
 <button onclick="myFunction()">点击这里</button>
 <p id="demo"></p>
 <script>
     function myFunction()
     {
         var x="",i=0;
         while (i<=10)
         {
             x=x + "The number is " + i + "<br>";
             i++;
         }
         document.getElementById("demo").innerHTML=x;
     }
 </script>