javascript自定义滚动条插件.

浏览数：18 / 时间：2015年06月08日

在实际项目中，经常由于浏览器自带的滚动条样式太戳，而且在各个浏览器中显示不一样，所以我们不得不去实现自定义的滚动条，今天我就用最少的代码实现了一个自定义滚动条，代码量区区只有几十行，使用起来也非常方便。

<!DOCTYPE html>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>自定义滚动条</title>
<style type="text/css">
body,ul,dl,dd{ margin:0; padding:0; font-size:12px; font-family:‘微软雅黑‘;}
.clear{ zoom:1}
.clear:after{ display:block; content:""; clear:both}
.box{margin:28px auto; width:164px; height:440px; background:#000; padding:8px;}
#wrap{ width:170px; height:386px; background:#1c1c1d; overflow:hidden; position:relative; }
#listbox{ float:left; width:160px; position:absolute; left:0; top:0; }
#scrollbox{ float:right; width:3px; height:386px; background: #333; position:relative;}
#scrollbar{ width:3px; height:30px; background:#cc3f2e; position:absolute; left:0; top:0;}

li{ height:80px; margin-bottom:8px; list-style:none;}
.picbox,.div{ float:left;}
.picbox{ width:150px; position:relative; }
.picbox span{ position:absolute; left:0px; bottom:0px; width:90px; height:22px;}
dl{ width:139px; height:76px; color:#fff; padding:4px 0 0 10px;line-height:18px; position:absolute;left:0; top:0; opacity:0.2; filter:alpha(opacity=20); }
.div{width:149px; height:80px; position:relative; }
.mark{width:149px; height:80px; position:absolute; top:0; left:0; background:#fff; opacity:0.1; filter:alpha(opacity=10);}

.nav{ width:160px; height:35px; font-family:‘微软雅黑‘;background:#1c1c1d; padding-top:5px;}
.a,.b{ width:152px; height:24px; line-height:24px; background:#666; text-align:center; float:left; color:#fff; cursor:pointer}
.a{margin-right:5px; display:inline; background:#333; color:#666; }

li.active .mark{opacity:0.2; filter:alpha(opacity=20);}
li.active dl{ opacity:0.7; filter:alpha(opacity=70);}
</style>
</head>
<body>
  <div class="box">
    <div class="nav">
      <div class="a">猜你喜欢</div>
    </div>
    <div id="wrap">
      <ul id="listbox">
        <li class="active">
          <div class="picbox">
            <span class="a1"></span>
          </div>
          <div class="div">
            <div class="mark"></div>
            <dl class="textbox">
              <dt>飞狐外传</dt>
              <dd>主演：方力申 周秀娜 谈莉娜 周秀娜施展媚术</dd>
              <dd>史上身材最棒狐仙</dd>
            </dl>
          </div>
        </li>
        <li>
          <div class="picbox">
            <span class="a2"></span>
          </div>
          <div class="div">
            <div class="mark"></div>
            <dl class="textbox">
              <dt>飞狐外传</dt>
              <dd>主演：方力申 周秀娜 谈莉娜 周秀娜施展媚术</dd>
              <dd>史上身材最棒狐仙</dd>
            </dl>
          </div>
        </li>
        <li>
          <div class="picbox">
            <span class="a2"></span>
          </div>
          <div class="div">
            <div class="mark"></div>
            <dl class="textbox">
              <dt>飞狐外传</dt>
              <dd>主演：方力申 周秀娜 谈莉娜 周秀娜施展媚术</dd>
              <dd>史上身材最棒狐仙</dd>
            </dl>
          </div>
        </li>
        <li>
          <div class="picbox">
            <span></span>
          </div>
          <div class="div">
            <div class="mark"></div>
            <dl class="textbox">
              <dt>飞狐外传</dt>
              <dd>主演：方力申 周秀娜 谈莉娜 周秀娜施展媚术</dd>
              <dd>史上身材最棒狐仙</dd>
            </dl>
          </div>
        </li>
        <li>
          <div class="picbox">
          </div>
          <div class="div">
            <div class="mark"></div>
            <dl class="textbox">
              <dt>飞狐外传</dt>
              <dd>主演：方力申 周秀娜 谈莉娜 周秀娜施展媚术</dd>
              <dd>史上身材最棒狐仙</dd>
            </dl>
          </div>
        </li>
        <li>
          <div class="picbox">
          </div>
          <div class="div">
            <div class="mark"></div>
            <dl class="textbox">
              <dt>飞狐外传</dt>
              <dd>主演：方力申 周秀娜 谈莉娜 周秀娜施展媚术</dd>
              <dd>史上身材最棒狐仙</dd>
            </dl>
          </div>
        </li>
        <li>
          <div class="picbox">
          </div>
          <div class="div">
            <div class="mark"></div>
            <dl class="textbox">
              <dt>飞狐外传</dt>
              <dd>主演：方力申 周秀娜 谈莉娜 周秀娜施展媚术</dd>
              <dd>史上身材最棒狐仙</dd>
            </dl>
          </div>
        </li>
        <li>
          <div class="picbox">
          </div>
          <div class="div">
            <div class="mark"></div>
            <dl class="textbox">
              <dt>飞狐外传</dt>
              <dd>主演：方力申 周秀娜 谈莉娜 周秀娜施展媚术</dd>
              <dd>史上身材最棒狐仙</dd>
            </dl>
          </div>
        </li>
        <li>
          <div class="picbox">
          </div>
          <div class="div">
            <div class="mark"></div>
            <dl class="textbox">
              <dt>飞狐外传</dt>
              <dd>主演：方力申 周秀娜 谈莉娜 周秀娜施展媚术</dd>
              <dd>史上身材最棒狐仙</dd>
            </dl>
          </div>
        </li>
        <li>
          <div class="picbox">
          </div>
          <div class="div">
            <div class="mark"></div>
            <dl class="textbox">
              <dt>飞狐外传</dt>
              <dd>主演：方力申 周秀娜 谈莉娜 周秀娜施展媚术</dd>
              <dd>史上身材最棒狐仙</dd>
            </dl>
          </div>
        </li>
        <li>
          <div class="picbox">
          </div>
          <div class="div">
            <div class="mark"></div>
            <dl class="textbox">
              <dt>飞狐外传</dt>
              <dd>主演：方力申 周秀娜 谈莉娜 周秀娜施展媚术</dd>
              <dd>史上身材最棒狐仙</dd>
            </dl>
          </div>
        </li>
      </ul>
      <div id="scrollbox">
        <div id="scrollbar"></div>
      </div>
    </div>
  </div>
</body>

<script src="tinyScroll.js"></script>
<script>
    new tinyScroll({
        wrapBox : document.getElementById(‘wrap‘),
        wrapList : document.getElementById(‘listbox‘),
        scrollBox :document.getElementById(‘scrollbox‘),
        scrollBar : document.getElementById(‘scrollbar‘)
    })
</script>
</html>

然后引入滚动条插件：

/**
 * javascript自定义滚动条(滚动条高度可以动态改变)
 * @param opts
 * 调用方式
 * new tinyScroll({
        wrapBox : document.getElementById(‘wrap‘),
        wrapList : document.getElementById(‘listbox‘),
        scrollBox :document.getElementById(‘scrollbox‘),
        scrollBar : document.getElementById(‘scrollbar‘)
    })
 */
function tinyScroll(opts) {
    this.wrapBox = opts.wrapBox;
    this.wrapList = opts.wrapList;
    this.scrollBox = opts.scrollBox;
    this.scrollBar = opts.scrollBar;
    this.scale = 0;
    this.height = 0;
    this.maxTop = 0;
    this.ListMaxTop = 0;
    this.top = 0;

    this.bindEvent();
}
tinyScroll.prototype = {
    constructor: tinyScroll,
    init: function() {
        this.scale = this.wrapBox.clientHeight / this.wrapList.scrollHeight;
        if (this.scale > 1) this.scale = 1;
        this.height = this.scale * this.scrollBox.scrollHeight;
        this.maxTop = this.scrollBox.scrollHeight - this.height;
        this.ListMaxTop = this.wrapBox.clientHeight - this.wrapList.scrollHeight;
        if (this.scale == 1) this.scrollBox.style.display = ‘none‘;
        this.scrollBar.style.height = this.height + ‘px‘;
    },
    bindEvent: function() {
        var that = this;
        var mouseScroll = function(ev) {
            ev = ev || event;
            var fx = ev.wheelDelta || ev.detail;
            var bDown = true;
            if (ev.detail) {
                bDown = fx > 0 ? true: false;
            } else {
                bDown = fx > 0 ? false: true;
            }
            if (bDown) {
                that.top += 10;
            } else {
                that.top -= 10;
            }
            that.fnScroll();
            if (ev.preventDefault) {
                ev.preventDefault();
            }
            return false;
        };
        this.init();
        this.scrollBar.onmousedown = function(ev) {
            ev = ev || event;
            var disY = ev.clientY - this.offsetTop;
            document.onmousemove = function(ev) {
                ev = ev || event;
                that.top = ev.clientY - disY;
                that.fnScroll();
            };
            document.onmouseup = function() {
                document.onmouseup = document.onmousemove = null;
            };
            return false;
        };
        this.wrapBox.onmousewheel = mouseScroll;
        if (this.wrapList.addEventListener) {
            this.wrapList.addEventListener(‘DOMMouseScroll‘, mouseScroll, false);
        }
    },
    fnScroll: function() {
        if (this.top < 0) this.top = 0;
        if (this.top > this.maxTop) this.top = this.maxTop;
        var scale = this.top / this.maxTop;
        var listTop = scale * this.ListMaxTop;
        this.scrollBar.style.top = this.top + ‘px‘;
        this.wrapList.style.top = listTop + ‘px‘;
    }
};