经典三栏布局

采用浮动的方式

<!DOCTYPE>
<html>
    <head>
        <meta charset="utf-8">
        <title>三栏布局</title>
        <style>
            *{
                padding: 0;
                margin: 0;
            }
            
            #wrap1{
                margin: 0 100px;
            }
            #wrap div{
                height: 300px;
            }
            #wrap .left{
                float: left;
                 200px;
                background: green;
            }
            #wrap .content{
                margin: 0 200px;
                background: red;
            }
            #wrap .right{
                float: right;
                 200px;
                background: yellow;
            }
        </style>
    </head>
    <body>
        <div id="wrap">
            <div class="left"></div>
            <div class="right"></div>
            <div class="content"></div>
        </div>
    </body>
</html>

采用flex方式

<!DOCTYPE>
<html>
    <head>
        <meta charset="utf-8">
        <title>三栏布局</title>
        <style>
            *{
                padding: 0;
                margin: 0;
            }

            #wrap{
                margin: 20px 100px;
                display: flex;
                flex-flow: row nowrap;
            }
            #wrap div{
                height: 300px;
            }
            #wrap .left{
                flex-grow: 0;
                 200px;
                background: green;
            }
            #wrap .content{
                flex: 1 1 auto;
                background: red;
            }
            #wrap .right{
                flex-grow: 0; 
                 200px;
                background: yellow;
            }
        </style>
    </head>
    <body>
        <div id="wrap">
            <div class="left"></div>
            <div class="content"></div>
            <div class="right"></div>
        </div>
    </body>
</html>

目前感觉这两种方式比较实用，欢迎补充