在字符串中查找 "ain" - 在线编辑器

          <p id="demo">单击按钮显示matches</p>
<button onclick="myFunction()">点我</button>
<script>
  function myFunction() {
    var str = "The rain in SPAIN stays mainly in the plain";
    var n = str.match(/ain/g);
    document.getElementById("demo").innerHTML = n;
  }
</script>
        