jQuery---弹幕效果

doctype html>
html>

head>
  meta charset="utf-8">
  title>title>
  style type="text/css">
    html,
    body {
      margin: 0px;
      padding: 0px;
      width: 100%;
      height: 100%;
      font-family: "微软雅黑";
      font-size: 62.5%;
    }

    .boxDom {
      width: 100%;
      height: 100%;
      position: relative;
      overflow: hidden;
    }

    .idDom {
      width: 100%;
      height: 50px;
      background: #666;
      position: fixed;
      bottom: 0px;
    }

    .content {
      display: inline-block;
      width: 430px;
      height: 40px;
      position: absolute;
      left: 0px;
      right: 0px;
      top: 0px;
      bottom: 0px;
      margin: auto;
    }

    .title {
      display: inline;
      font-size: 4em;
      vertical-align: bottom;
      color: #fff;
    }

    .text {
      border: none;
      width: 300px;
      height: 30px;
      border-radius: 5px;
      font-size: 2.4em;
    }

    .btn {
      width: 60px;
      height: 30px;
      background: #f90000;
      border: none;
      color: #fff;
      font-size: 2.4em;
    }

    span {
      width: 300px;
      height: 40px;
      position: absolute;
      overflow: hidden;
      color: #000;
      font-size: 4em;
      line-height: 1.5em;
      cursor: pointer;
      white-space: nowrap;
    }
  style>
head>

body>

  div class="boxDom" id="boxDom">
    div class="idDom" id="idDom">
      div class="content">
        p class="title">弹幕:p>
        input type="text" class="text" id="text" />
        button type="button" class="btn" id="btn">发射button>
      div>
    div>
  div>
body>

script src="jquery-1.12.4.js">script>
script>

  $(function () {

    //注册事件
    var colors = ["red", "green", "orange", "yellow", "hotpink", "purple", "cyan"];
    $("#btn").click(function () {
      var randomColor = parseInt(Math.random() * colors.length);
      var randomY = parseInt(Math.random() * 400);
      $("")
        .text($("#text").val())//设置内容
        .css("color", colors[randomColor])//设置字体颜色
        .css("left", 1400)//设置left值
        .css("top", randomY)//设置top值
        .animate({ left: -500 }, 10000, "linear", function () {
          //到了终点，需要删除
          $(this).remove();
        })
        .appendTo("#boxDom");

      $("#text").keyup(function (e) {
        if (e.keyCode == 13) {
          $("#btn").click();
        }
      });
    });
  });

script>

html>