JavaScript定时器实现方块移动控制示例

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <title>www.jb51.net 定时器的应用</title>
  <style>
    #Div1 { width: 100px; height: 100px; position: absolute; background-color: red; top: 50px; }
  </style>
</head>
<body>
<input id="oBtn1" type="button" value="铵钮">
<div id="Div1"></div>
<script>
  var oBtn = document.getElementById("oBtn1");
  var oDiv = document.getElementById("Div1");
  //var timer=null;
  //oDiv.timer=null;
  oBtn.onclick = function() {
    clearInterval(oDiv.timer)
    oDiv.timer = setInterval(function() {
      var speed = parseInt(getStyle(oDiv, "left")) + 9;
      if(speed > 800) {
        speed = 800;
      }
      oDiv.style.left = speed + "px"
      if(speed == 800) {
        clearInterval(oDiv.timer);
        //alert(speed)
      }
    }, 50)
  }
  function getStyle(obj, attr) {
    return obj.currentStyle ? obj.currentStyle[attr] : getComputedStyle(obj)[attr]
  }
</script>
</body>
</html>