xxxxxxxxxx<html><head><meta charset="utf-8"><title>W3Cschool教程(w3cschool.cn)</title></head><body><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<5){ x=x + "该数字为 " + i + "<br>"; i++; } document.getElementById("demo").innerHTML=x;}</script></body></html>