本文主要是介绍js 实现弹幕效果，希望对大家解决编程问题提供一定的参考价值，需要的开发者们随着小编来一起学习吧！
效果图
注入灵魂
<!DOCTYPE html>
<html lang="en">
<head><meta charset="UTF-8"><meta name="viewport" content="width=id, initial-scale=1.0"><title>Document</title><style type="text/css">*{ margin: 0; padding: 0;}#box{ width: 542px; height: 330px;border: 3px solid goldenrod;margin-left:300px;}#btm{margin: 0;padding: 0; height: 30px;background: goldenrod;display: flex; z-index: 999; position: relative; }#btm span{ flex: 1; flex-direction: column;font: 16px/30px "微软雅黑";color: #fff; text-align: center; cursor: pointer;}#btm span:nth-child(1){ flex: 3;}#btm span input{ width:100% ; height: 30px; font: 16px/30px "微软雅黑";border: none; outline: none;}#content{ height: 300px; position: relative; z-index: 999;background:rgba(0,0,0,0.7)}#content span{color:#fff; height: 30px; font: 14px/30px "微软雅黑"; position: absolute;left:542px;white-space: nowrap;}#v{ position: absolute;left: 303px; top: -32px; width: 542px; height: 358px; background: url(2.png);}</style>
</head>
<body><div id="box"><div id="content"></div><p id="btm"><span><input type="text" id="text" /></span><span id="sendCon">发送</span><span id="hideCon">隐藏</span><span id="showCon">显示</span></p></div><div id="v"></div>
</body>
<script src="sport.js"></script>
<script>function $(id) {return document.getElementById(id)}// 封装一个函数，实现发送消息function sendMessage () {var oSpan = document.createElement('span');oSpan.innerHTML = $("text").value;$('content').appendChild(oSpan)oSpan.style.top = Math.floor(Math.random() * 280) + 'px'var oSpanWidth = oSpan.offsetWidth;startMove(oSpan,{"left": -oSpanWidth}, function(){oSpan.remove()})$("text").value = ''}// 鼠标发送按钮$('sendCon').onclick = function(){sendMessage();}// 键盘发送document.onkeydown = function (e) { // 回车提交表单// 兼容FF和IE和Operavar theEvent = window.event || e;var code = theEvent.keyCode || theEvent.which || theEvent.charCode;if (code == 13) {sendMessage();}}// 隐藏： 将运动得消息隐藏，背景图片亮度增强$('hideCon').onclick = function () {$('content').style.opacity = '0'$('content').style.filter = 'alpha(opacity=0)' // 该方法IE特有 兼容IE8以下的浏览器}// 显示： 弹幕继续向前运动 背景图片变模糊$('showCon').onclick = function () {$('content').style.opacity = '1'$('content').style.filter = 'alpha(opacity=1)' // 该方法IE特有 兼容IE8以下的浏览器}
</script>
</html>sport.js
function startMove(obj,json,fn){ // {"width":300,"height":300}clearInterval(obj.timer);obj.timer = setInterval(function(){var flag = true;// 当开关变量的值为 true时，运动结束，可以停止定时器了 for(var attr in json){ var current = 0;if(attr == "opacity"){//操作透明度debugger;current = parseFloat( getStyle( obj,attr ) ) * 100;console.log(current);}else if( attr == "zIndex" ){current = parseInt( getStyle(obj,attr) );//操作空间定位}else{//操作的是带有像素值的样式current = parseInt( getStyle(obj,attr) );//获取当前操作对象的实际值}var speed = (json[attr] - current) > 0 ? 1 : -1;//speed = speed>0 ? Math.ceil(speed) : Math.floor(speed);if( json[attr] != current ){//如果目标值 和 当前操作的样式值不相等，就不能停止定时器 flag = false; }//上面的条件不满足 继续执行运动if(attr == "opacity"){//操作透明度obj.style.opacity = (current + speed) / 100;}else if(attr == "zIndex"){obj.style.zIndex = current+speed;}else{//操作的是带有像素值的样式obj.style[attr] = current + speed + "px";} } //如果flag为true 就停止定时器 if(flag){clearInterval(obj.timer);//一个动作完成后,进入下一个动作(也就是要调用下一个函数)if(fn){ //判断如果有函数传递过来，就调用fn();}}},10)}function getStyle(obj,attr){return window.getComputedStyle ? window.getComputedStyle(obj,false)[attr] : obj.currentStyle[attr];}
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