实例 »

<p>设置 x=10 和 y=5, 计算 x-=y, 并显示结果。</p>

<button onclick="myFunction()">点我</button>

<p id="demo"></p>

<script>

  function myFunction() {

    var x = 10;

    var y = 5;

    x -= y;

    var demoP = document.getElementById("demo")

    demoP.innerHTML = "x=" + x;

  }

</script>