• CSS


    1、css的简介

    (1)什么是css

        层叠样式表,css是对html进行样式修饰语言

        层叠:就是层层覆盖叠加,如果不同的css样式对同一html标签进行修饰,样式有冲突的部分应用优先级高的,不冲突的部分共同作用。

        样式表:就是css属性样式的集合

    (2)css的作用

             a . 修饰html的 使其html样式更加好看

       b . 提高样式代码的复用性

       c . html的内容与样式相分离 便于后期维护

    (3)css的引入方式和书写规范

             a . 内嵌样式

         内嵌样式是把css的代码嵌入到html标签中   

    <div style = "color:red;font-size: 100px;">你好啊 小朋友</div>

              运行效果 :

                 

                  语法:

                           。使用style属性将样式嵌入到html标签中

            。属性的写法:属性:属性值

               。多个属性之间使用分号;隔开

                   不建议使用

             b . 内部样式

    <style type="text/css">
        div{color:blue;font-size: 100px;}
    </style>

                 在head标签中使用style属性进行css的引入  

        语法:

                           。使用style标签进行css的引入

                               <style type = "text/css">

            属性:type:告知浏览器使用css解析器去解析

            。属性的写法:属性:属性值

               。多个属性之间使用分号;隔开

             c . 外部样式

        将css样式抽取成一个单独css文件 谁去使用谁去引用

    <link rel = "stylesheet" type = "text/css" href = "demo1.css">

                语法:

           。创建css文件 将css属性写在css文件中

                 。在head标签中使用link标签进行引入  

                                ref : 代表要引入的文件和html的关系

                    type : 告知浏览器使用css解析器去解析

                                href : css文件地址

           。属性的写法:属性:属性值

              。多个属性之间使用分号;隔开 

    2、css选择器

          (1)基本选择器

                    a  元素选择器

                       语法:html标签名{css属性}

                    示例:

    <!DOCTYPE html>
    <html>
    <head>
    <meta charset="UTF-8">
    <title>Insert title here</title>
    
    <style type="text/css">
        span{color:blue;font-size: 100px;}
    </style> 
    
    </head>
    <body>
        <span>hello css!</span>
    </body>
    </html>

                   b   id选择器  id唯一性

                 语法:#id的值{css属性}

                       例子:

    <!DOCTYPE html>
    <html>
    <head>
    <meta charset="UTF-8">
    <title>Insert title here</title>
    
    <style type="text/css">
        #div1{background-color: red;}
        #div2{background-color: pink;}
    </style> 
    
    </head>
    <body>
        <div id = "div1">hello css1!!!</div>
        <div id = "div2">hello css2!!!</div>
    </body>
    </html>

                效果:

               

                 c     class选择器 

                       语法:  .class的值{css属性}

                        示例:

    <!DOCTYPE html>
    <html>
    <head>
    <meta charset="UTF-8">
    <title>Insert title here</title>
    
    <style type="text/css">
        .style1{background-color: red;}
        .style2{background-color: pink;}
    </style> 
    
    </head>
    <body>
        <div class = "style1">hello css1!!!</div>
        <div class = "style1">hello css2!!!</div>
        <div class = "style2">hello css3!!!</div>
    </body>
    </html>

            效果:

           

           (重点)选择器的优先级:id > class > 元素选择器

       (2)属性选择器

                   语法:基本选择器[属性='属性值']{css属性}

                   示例: 

    <!DOCTYPE html>
    <html>
    <head>
    <meta charset="UTF-8">
    <title>Insert title here</title>
    
    <style type="text/css">
        input[type='text']{background-color: yellow}
        input[type='password']{background-color: pink}
    </style> 
         
    </head>
    <body>
        <form action="">
            name:<input type = "text"/><br>
            pass:<input type = "password"/><br>
        </form>
    </body>
    </html> 

          效果:

               

          (3)伪元素选择器

                   a 标签的伪元素选择器        

                     静止状态   a:link{css属性}

                     悬浮状态   a:hover{css属性}

                     触发状态  a:action{css属性}

                     完成状态  a:visited{css属性} 

    <!DOCTYPE html>
    <html>
    <head>
    <meta charset="UTF-8">
    <title>Insert title here</title>
    
    <style type="text/css">
        a:link{color:blue}
        a:hover{color:red}
        a:active{color:yellow}
        a:visited{color:green}
    </style> 
         
    </head>
    <body>
        <a href = "#">点击我吧</a>
    </body>
    </html>

      (4)层级选择器:

                     语法:父级选择器 子级选择器。。。

    <!DOCTYPE html>
    <html>
    <head>
    <meta charset="UTF-8">
    <title>Insert title here</title>
    
    <style type="text/css">
        #d1 .dd2 span{color:red}
    </style> 
         
    </head>
    <body>
        <div id = "d1">
            <div class = "dd1"> 
                <span>span1-1</span>
            </div>
            <div class = "dd2">
                <span>span1-2</span>
            </div>
        </div>
        <div id = "d2">
            <div class = "dd1">
                <span>span1-1</span>
            </div>
            <div class = "dd2">
                <span>span1-2</span>
            </div>
            </div>
        
    </body>
    </html>

    3、css属性

        (1)文字属性

        font-size : 大小

              font-family : 字体类型

    <!DOCTYPE html>
    <html>
    <head>
    <meta charset="UTF-8">
    <title>Insert title here</title>
    
    <style type="text/css">
        span{color:red;font-size:100px;font-family:黑体;}
    </style> 
         
    </head>
    <body>
        <span>hello css!</span>
    </body>
    </html>

        (2)文本属性

                  color : 颜色

                  text-decoration : 下划线

                               属性值:none underline

                 text-align : 对齐方式

    <!DOCTYPE html>
    <html>
    <head>
    <meta charset="UTF-8">
    <title>Insert title here</title>
    
    <style type="text/css">
        div{color:red;text-decoration:underline;text-align:left}
        a{text-decoration: none}
    </style> 
         
    </head>
    <body>
        <div>hello css!!!</div>
        <a href = "#">click me!!!</a>
    </body>
    </html>

        (3)背景属性

                  background-color : 背景颜色

                  background-image : 背景图片

                              属性值 : url("图片的地址");

                  background-repeat : 平铺方式

            属性值 : 默认横向纵向平铺

                                            repeat : 横向纵向平铺

                                            no-repeat : 不平铺

              repeat-x : 横向平铺

              repeat-y : 纵向平铺

    <!DOCTYPE html>
    <html>
    <head>
    <meta charset="UTF-8">
    <title>Insert title here</title>
    
    <style type="text/css">
        body{
            background-color:black;
            background-image: url("image/100.png");
            background-repeat: no-repeat;
        }
    </style> 
         
    </head>
    <body>
    
    </body>
    </html>

        (4)列表属性

                 list-style-type : 列表项前的小标志

                      属性值很多,不一一列举

                 list-style-image : 列表项前的小图片

                      属性值 : url("图片地址");

    <!DOCTYPE html>
    <html>
    <head>
    <meta charset="UTF-8">
    <title>Insert title here</title>
    
    <style type="text/css">
            /* ul{list-style-type:square;} */
            ul{list-style-image:url("image/222.png");}
    </style> 
         
    </head>
    <body>
        <ul>
            <li>天道酬勤</li>
            <li>天道酬勤</li>
            <li>天道酬勤</li>
        </ul>
    </body>
    </html>

     

        (5)尺寸属性

        width : 宽度

              height : 高度

    <!DOCTYPE html>
    <html>
    <head>
    <meta charset="UTF-8">
    <title>Insert title here</title>
    
    <style type="text/css">
        #d1{background-color: red;width:200px;height:200px;}
        #d2{background-color: pink;width:200px;height:200px;}
    </style> 
         
    </head>
    <body>
        <div id = "d1">div1</div>
        <div id = "d2">div2</div>
    </body>
    </html>

        (6)显示属性

                 display : 

           属性值:none : 隐藏

               block : 块级显示

               inline : 行级显示

    <!DOCTYPE html>
    <html>
    <head>
    <meta charset="UTF-8">
    <title>Insert title here</title>
    
    <style type="text/css">
        span{color:red;display:none}
    </style> 
         
    </head>
    <body>
        <form action = "">
            name:<input id = "name" type = "text"/><span id = "span">对不起 输入不符合要求</span>
            <br>
            pass:<input id = "pass" type = "password">
            <br>
            <input id = "btn" type = "button" value = "button">
        </form>
    </body>
    
    <script type="text/javascript">
        document.getElementById("btn").onclick = function(){
            document.getElementById("span").style.display = "inline";
        };
    </script>
    
    </html>

        (7)浮动属性

         float : 

            属性值 : left   right

               clear : 清除浮动 left right both

                 缺点 : 

          (1)影响相邻的元素不能正常显示

          (2)影响父元素不能正常显示

    <!DOCTYPE html>
    <html>
    <head>
    <meta charset="UTF-8">
    <title>Insert title here</title>
    
    <style type="text/css">
        #d1{width :200px;height :200px;background-color: red;float:left}
        #d2{width :200px;height :200px;background-color: blue;float:left}
    </style> 
         
    </head>
    <body>
        <div id = "d1"></div>
        <div id = "d2"></div>
    </body>
    
    </html>

    4、css盒子模型

       border :

        border - width : 边框的宽度

              border - color : 边框的颜色

                    border - style : 边框的线型

                    

          border - top : 上边框

                   border - bottom : 下边框

                   border - left : 左边框

                   border - right : 右边框

       padding : 

            代表边框内壁与内部元素之间的距离

         padding : 10px 代表上下左右都是10px

                  padding : 1px 2px 3px 4px;   上 右 下 左

            padding : 1px 2px;  上下/左右

         padding-top : 单独设置

        margin:      

             代表边框外壁与其他元素之间的距离

         margin : 10px 代表上下左右都是10px

                  margin : 1px 2px 3px 4px;   上 右 下 左

            margin : 1px 2px;  上下/左右

         margin-top : 单独设置

    <!DOCTYPE html>
    <html>
    <head>
    <meta charset="UTF-8">
    <title>Insert title here</title>
    
    <style type="text/css">
        #mooncake{width:100px;height:100px;background-color: red} 
        #box1{width:120px;height:120px;border:10px solid green;padding:20px;margin:50px}
    </style> 
         
    </head>
    <body>
        <div id = "box1">
            <div id = "mooncake">花好月圆</div>
        </div>
    </body>
    
    </html>

    图书商城案例:

    <!DOCTYPE html>
    <html>
    <head>
    <meta charset="UTF-8">
    <title>Insert title here</title>
    
    <style type="text/css">
        .clear{
            clear:both;
        }
        #top_left{
            width:300px;
            float:left;
        }
        #top_right{
            width:500px;
            float:right;
            margin-top:15px;
            font-size:13px;
        }
        #top_right a{
            text-decoration: none;
            color:#06F;
        }
        #top_right a:hover{
            color:#909;
        }
        #menu{
            background-color:#1C3F09;
            border-top:5px solid #82b211;
            padding:10px 0px;
            text-align: center;
        }
        #menu a{
            margin: 0 10px;
            color:#fff;
            text-decoration: none;
            font-weight: bold; 
            font-size: 15px; 
        }
        #menu a:hover{
            color:#999;
        }
        #menu .all{
            color:yellow;
        }
        #search{
            background-color: #B6B684;
            padding:7px 0;
            text-align: right;
            
        }
        #search input[type='image']{
            margin-right: 250px;
            margin-bottom:0px; 
        }
        #search input[type='text']{
            height:15px;
            border:1px solid #999;
        }
        #content{
            width:900px;
            /* border:1px solid #999; */
            margin:8px auto 15px   /*auto div居中*/
        }
        #content_top{
            text-align: right;
            text-size:13px;
        }
        #content_bottom{
            border:1px solid #999;
            background-color: #FCFDEF;
            padding : 10px 15px;
        }
        #content_bottom h1{
            font-size:15px;
            display:inline;
        }
        #content_bottom span{
            font-size:12px;
        }
        #product_list_img img{
            width:100%;
        }
        .book{
            float:left;
            width :25%;
            text-align: center;
            padding:10px 0;
        }
        .bookimg img{
            width:130px;
            height:196px;
        }
        #jumpPage{
            text-align:center;
            margin:10px;
        }
        #jumpPage a{
            padding:2px 6px;
            border:1px solid #9AAFE5;
            text-decoration: none;
            color:#9AAFE5;
        }
        #jumpPage a:hover{
            color:#2B66A5;
            border:1px solid #2B66A5;
        }
        .current{
            background-color: blue;
        }
        #bottom{
            background-color: #EFEEDC;
            height:80px;
            padding:10px 0;
        }
        #bottom_left{
            width:400px;
            float: left;
        }
        #bottom_right{
            width:500px;
            float: right;
            line-height:28px;  /*行高*/
        } 
        
    </style>
    
    </head>
    <body>
        <div id = "page">
            <div id = "top">
                <div id = "top_left">
                    <img alt="" src="image/logo.png">
                </div>
                <div id = "top_right">
                    <img alt="" src="image/cart.png">
                    <a href = "#">购物车</a>
                    <a href = "#">帮助中心</a>
                    <a href = "#">我的账户</a>
                    <a href = "#">新用户注册</a>
                </div>
            </div>
            <div class = "clear"></div>
            <div id = "menu">
                <a href = "#">文学</a>
                <a href = "#">生活</a>
                <a href = "#">计算机</a>
                <a href = "#">外语</a>
                <a href = "#">经管</a>
                <a href = "#">社科</a>
                <a href = "#">学术</a>
                <a href = "#">少儿</a>
                <a href = "#">艺术</a>
                <a href = "#">原版</a>
                <a href = "#">考试</a>
                <a href = "#">生活百科</a>
                <a class = "all" href = "#">全部目录商品</a>
            </div>
            <div id = "search">
                <span>Search</span>
                <input type = "text">
                <input type = "image" src = "image/searchbutton.png">
            </div>
            <div id = "content">
                <div id = "content_top">
                    <span>首页&nbsp;&gt;&nbsp;旅游&nbsp;&gt;&nbsp;图书列表</span>
                </div>
                <div id = "content_bottom">
                    <h1>商品目录</h1>
                    <hr>
                    <h1>计算机类</h1>
                    <span>共100种商品</span>
                    <hr>
                    <div id = "product_list">
                        <div id = "product_list_img">
                            <img alt="" src="image/productlist.png">
                        </div>
                        <div id = "booklist">
                            <div class = "book">
                                <div class = "bookimg">
                                    <img alt="" src="image/100.png">
                                </div>
                                <div class = "bookIntr">
                                    <span>书名:XXX</span><br>
                                    <span>售价:XXX</span>
                                </div>
                            </div>
                            <div class = "book">
                                <div class = "bookimg">
                                    <img alt="" src="image/101.png">
                                </div>
                                <div class = "bookIntr">
                                    <span>书名:XXX</span><br>
                                    <span>售价:XXX</span>
                                </div>
                            </div>
                            <div class = "book">
                                <div class = "bookimg">
                                    <img alt="" src="image/102.png">
                                </div>
                                <div class = "bookIntr">
                                    <span>书名:XXX</span><br>
                                    <span>售价:XXX</span>
                                </div>
                            </div>
                            <div class = "book">
                                <div class = "bookimg">
                                    <img alt="" src="image/103.png">
                                </div>
                                <div class = "bookIntr">
                                    <span>书名:XXX</span><br>
                                    <span>售价:XXX</span>
                                </div>
                            </div>
                            <div class = "book">
                                <div class = "bookimg">
                                    <img alt="" src="image/104.png">
                                </div>
                                <div class = "bookIntr">
                                    <span>书名:XXX</span><br>
                                    <span>售价:XXX</span>
                                </div>
                            </div>
                            <div class = "book">
                                <div class = "bookimg">
                                    <img alt="" src="image/104.png">
                                </div>
                                <div class = "bookIntr">
                                    <span>书名:XXX</span><br>
                                    <span>售价:XXX</span>
                                </div>
                            </div>
                            <div class = "book">
                                <div class = "bookimg">
                                    <img alt="" src="image/105.png">
                                </div>
                                <div class = "bookIntr">
                                    <span>书名:XXX</span><br>
                                    <span>售价:XXX</span>
                                </div>
                            </div>
                            <div class = "book">
                                <div class = "bookimg">
                                    <img alt="" src="image/106.png">
                                </div>
                                <div class = "bookIntr">
                                    <span>书名:XXX</span><br>
                                    <span>售价:XXX</span>
                                </div>
                            </div>
                            <div class = "clear"></div>
                            <div id = "jumpPage">
                                <a href = "#">上一页</a>
                                <a class = "current" href = "#">1</a>
                                <a href = "#">2</a>
                                <a href = "#">3</a>
                                <a href = "#">4</a>
                                <a href = "#">5</a>
                                <a href = "#">6</a>
                                <a href = "#">7</a>
                                <a href = "#">下一页</a>
                            </div>
                        </div>
                    </div>
                </div>
            </div>
            <div id = "bottom">
                <div id = "bottom_left"></div>
                    <img alt="" src="image/logo.png">
                <div id = "bottom_right">
                    <span>CONTACT US</span><br>
                    <span>copyright 2017&copy;BookStore All Rights RESERVED</span>
                </div>
            </div>
        </div>
    </body>
    </html>

    效果如下:

     

    案例中所用到的图片资源放到这里了:http://download.csdn.net/download/little_frog_prince/10138403

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  • 原文地址:https://www.cnblogs.com/2-NARUTO-2/p/7932292.html
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