为什么字符串在一定间隔内不移动？

Question

我正在尝试编写一个简单的代码，每 20 毫秒移动 1 像素的直线（smt 就像一个自动收报机）。此外，使用 .offsetWidth 属性希望它在到达浏览器 window 的边缘后消失。不幸的是，我卡住了，我不知道为什么它根本不动。请帮我找出错误，或者我走错了方向？谢谢！

<html>
<head>
    <title>Blablabla</title>
    <meta charset ="utf-8">
    <!-- <script type="text/javascript" src="line.js"></script> -->
</head>
<body onload="interval()">
    <div id="line">
    Lorem ipsum dolor sit amet, consectetur adipisicing elit, sed do eiusmod
    </div>
<script type="text/javascript">
    function interval() {
        var line = setInterval(function(){document.getElementById("line").style.left = scroll.offsetWidth}, 20);
    }
</script>
</body>
</html>

Answer 1

line 必须是 absolute 定位的元素，这样 left css 属性会影响
我假设您在将 interval 中的 left 属性分配为 element.offsetWidth does not return unit with the value[Ref]

+px(unit)

Answer 2

看看下面的示例，它的注释应该可以帮助您理解、查看演示并尝试代码

//set starting offset
var leftOffset = 0;

//assign element to variable
var element = document.getElementById("line");

//css.left requires position.absolute
element.style.position = 'absolute';

//calculate width of element, in display.block it's 100%
element.style.display = 'inline-block';

//assign interval id to a variable for cancelation
var interval = setInterval(function(){
  
  //increase offset by 1
  leftOffset = leftOffset + 1;

  //check if element is sticked  to screen.right
  if(leftOffset + element.offsetWidth < document.body.offsetWidth) {
    //not sticked
    
    //add pixels
    element.style.left = leftOffset + 'px';
  } else {
    //sticked

    //remove interval
    clearInterval(interval);
    
    //hide element
    element.style.display = 'none';
  }
}, 20);

<div id="line">
  Lorem ipsum dolor sit amet, consectetur adipisicing elit, sed do eiusmod
</div>

Answer 3

这是我的镜头：

<html>
<head>
    <title>Blablabla</title>
    <meta charset ="utf-8">
    <!-- <script type="text/javascript" src="line.js"></script> -->
</head>
<body>
    <div id="line">
    Lorem ipsum dolor sit amet, consectetur adipisicing elit, sed do eiusmod
    </div>
<script type="text/javascript">
number = 5; //should be increased each time
setInterval(function(){var d = document.getElementById('line');
d.style.position = "absolute";
number++; //increase number
d.style.left = number; //move the div according to the number
}, 200); //notice that you can increase/decrease 200 according to your will

</script>
</body>
</html>

为什么字符串在一定间隔内不移动？

Why does the string not moving within the certain interval?

javascript

string

setinterval

offsetwidth