js键盘控制方块移动

最新推荐文章于 2024-12-04 14:50:55 发布

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最新推荐文章于 2024-12-04 14:50:55 发布

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文章标签： javascript

本文链接：https://blog.youkuaiyun.com/Ga_b_c/article/details/107452208

<style>
    * {
      padding: 0;
      margin: 0;
    }

    .box {
      width: 100px;
      height: 100px;
      background-color: #6ff;
      position: absolute;
      left: 0;
      top: 0;
    }
  </style>

<div class="box"></div>
<script>
  var oBox = document.querySelector('.box');

  var maxLeft = document.documentElement.clientWidth - oBox.offsetWidth;
  var maxTop = document.documentElement.clientHeight - oBox.offsetHeight;

  document.onkeydown = function (e) {
    // console.log(666);
    // 初始位置
    var left = oBox.offsetLeft;
    var top = oBox.offsetTop;

    // console.log(left, top);

    var ev = event || e;
    var keyCode = ev.keyCode || ev.which;

    // console.log(keyCode);

    // return

    // // 位移
    // left += 10;

    switch (keyCode) {
      case 37: left -= 10; break;
      case 39: left += 10; break;
      case 38: top -= 10; break;
      case 40: top += 10; break;
    }

    if (left <= 0) {
      left = 0;
    }

    if (left >= maxLeft) {
      left = maxLeft;
    }

    if (top <= 0) {
      top = 0;
    }

    if (top >= maxTop) {
      top = maxTop;
    }

    // 给新位置
    oBox.style.top = top + 'px';
    oBox.style.left = left + 'px';
  }
</script>