CSS的内容溢出和剪裁:overflow

CSS的内容溢出和剪裁:overflow

     为什么要使用overflow：

       html中经常会出现子元素的宽度或高度超过了

      父元素的高度或宽度。页面上的显示内容就会超出

      父元素的边框。可以通过overflow进行控制处理。

      overflow介绍:

        滚动条样式主要涉及到如下overflow属性:

        overflow属性: 检索或设置当对象的内容超过其指定高度及宽度时如何显示内容，其用到的表现形式和值有以下几种

        overflow: auto; 在需要时内容会自动添加滚动条
        overflow: scroll; 总是显示滚动条
        overflow-x: hidden; 禁止横向的滚动条
        overflow-y: scroll; 总是显示纵向滚动条

        以上属性设置的值为visible、scroll、hidden、auto

        visible 默认值。使用该值时，无论设置的"width"和"height"的值是多少，其中的内容无论是否超出范围都将被强制显示。
        hidden 效果与visible相反。任何超出"width"和"height"的内容都会不可见。
        scroll 无论内容是否超越范围，都将显示滚动条。
        auto 当内容超出范围时，显示滚动条，否则不显示。

     

      overflow 可实现的功能：横向列表和纵向列表

      下面将实现的功能：纵向列表

      功能描述：需要将内容按列表纵向显示，超出的部分可以通过滚动框拖动显示。

      实现的效果：

     

    实现思路：

    1.布局：    最外层div包含顶部标签div和列表ul,固定ul的高度为300px;

    摆放超过5个li 的item;

    2.CSS    设置overflow-y为auto  ,overflow-x为hidden并设置相应的颜色样式；

    布局图：

   

 

      实现代码:

      html：

     

<div class="rankinglist">                <div class="rankTag bgcolor_21-126-130">积分排行</div>                <ul class="ranklist">                    <li class="rankli integralli">                        <div class="rankliitem">                            <div class="info left">                                <img class="gamelogoimgtop" src="../images/homepage/dangzhou.png">                            </div>                            <div class="info middle">                                <div class="middlesub">                                    战无不胜                                </div>                                <div class="clear"></div>                                <div class="middlesub">                                    <img class="gamelogoimgsmall" src="../images/homepage/dangzhou.png">                                </div>                                <div class="middlesubdownright">2</div>                                <div class="clear"></div>                            </div>                            <div class="info right">NO.1</div>                            <div class="clear"></div>                        </div>                        <div class="h2 bgcolor_cccccc"></div>                    </li>                    <li class="rankli integralli">                        <div class="rankliitem">                            <div class="info left">                                <img class="gamelogoimgtop" src="../images/homepage/dangzhou.png">                            </div>                            <div class="info middle">                                <div class="middlesub">                                    战无不胜                                </div>                                <div class="clear"></div>                                <div class="middlesub">                                    <img class="gamelogoimgsmall" src="../images/homepage/dangzhou.png">                                </div>                                <div class="middlesubdownright">2</div>                                <div class="clear"></div>                            </div>                            <div class="info right">NO.1</div>                            <div class="clear"></div>                        </div>                        <div class="h2 bgcolor_cccccc"></div>                    </li>                    <li class="rankli integralli">                        <div class="rankliitem">                            <div class="info left">                                <img class="gamelogoimgtop" src="../images/homepage/dangzhou.png">                            </div>                            <div class="info middle">                                    <div class="middlesub">                                        战无不胜                                    </div>                                    <div class="clear"></div>                                    <div class="middlesub">                                        <img class="gamelogoimgsmall" src="../images/homepage/dangzhou.png">                                    </div>                                    <div class="middlesubdownright">2</div>                                    <div class="clear"></div>                            </div>                            <div class="info right">NO.1</div>                            <div class="clear"></div>                        </div>                        <div class="h2 bgcolor_cccccc"></div>                    </li>                    <li class="rankli integralli">                        <div class="rankliitem">                            <div class="info left">                                <img class="gamelogoimgtop" src="../images/homepage/dangzhou.png">                            </div>                            <div class="info middle">                                <div class="middlesub">                                    战无不胜                                </div>                                <div class="clear"></div>                                <div class="middlesub">                                    <img class="gamelogoimgsmall" src="../images/homepage/dangzhou.png">                                </div>                                <div class="middlesubdownright">2</div>                                <div class="clear"></div>                            </div>                            <div class="info right">NO.2</div>                            <div class="clear"></div>                        </div>                        <div class="h2 bgcolor_cccccc"></div>                    </li>                    <li class="rankli integralli">                        <div class="rankliitem">                            <div class="info left">                                <img class="gamelogoimgtop" src="../images/homepage/dangzhou.png">                            </div>                            <div class="info middle">                                <div class="middlesub">                                    战无不胜                                </div>                                <div class="clear"></div>                                <div class="middlesub">                                    <img class="gamelogoimgsmall" src="../images/homepage/dangzhou.png">                                </div>                                <div class="middlesubdownright">2</div>                                <div class="clear"></div>                            </div>                            <div class="info right">NO.3</div>                            <div class="clear"></div>                        </div>                        <div class="h2 bgcolor_cccccc"></div>                    </li>                    <li class="rankli integralli">                        <div class="rankliitem">                            <div class="info left">                                <img class="gamelogoimgtop" src="../images/homepage/dangzhou.png">                            </div>                            <div class="info middle">                                <div class="middlesub">                                    战无不胜                                </div>                                <div class="clear"></div>                                <div class="middlesub">                                    <img class="gamelogoimgsmall" src="../images/homepage/dangzhou.png">                                </div>                                <div class="middlesubdownright">2</div>                                <div class="clear"></div>                            </div>                            <div class="info right">NO.4</div>                            <div class="clear"></div>                        </div>                        <div class="h2 bgcolor_cccccc"></div>                    </li>                    <li class="rankli integralli">                        <div class="rankliitem">                            <div class="info left">                                <img class="gamelogoimgtop" src="../images/homepage/dangzhou.png">                            </div>                            <div class="info middle">                                <div class="middlesub">                                    战无不胜                                </div>                                <div class="clear"></div>                                <div class="middlesub">                                    <img class="gamelogoimgsmall" src="../images/homepage/dangzhou.png">                                </div>                                <div class="middlesubdownright">2</div>                                <div class="clear"></div>                            </div>                            <div class="info right">NO.5</div>                            <div class="clear"></div>                        </div>                        <div class="h2 bgcolor_cccccc"></div>                    </li>                </ul>            </div>

           CSS:

.nav .ranking .ranklist{    height: 300px;    overflow-y: auto;    overflow-x: hidden;    scrollbar-arrow-color: #f4ae21; /**//*三角箭头的颜色*/    scrollbar-face-color: #333; /**//*立体滚动条的颜色*/    scrollbar-3dlight-color: #666; /**//*立体滚动条亮边的颜色*/    scrollbar-highlight-color: #666; /**//*滚动条空白部分的颜色*/    scrollbar-shadow-color: #999; /**//*立体滚动条阴影的颜色*/    scrollbar-darkshadow-color: #666; /**//*立体滚动条强阴影的颜色*/    scrollbar-track-color: #666; /**//*立体滚动条背景颜色*/    scrollbar-base-color:#f8f8f8; /**//*滚动条的基本颜色*/}