SOURCE

<div class="main">
    <div class="middle">
        <div class="content">
            中间
        </div>
    </div>
    <div class="left">
        左边
    </div>
    <div class="right">
        右边
    </div>
</div>

* {
    margin: 0;
    padding: 0;
}

body,
html {
    width: 100%;
    height: 100%;
}
div{
    height: 100%;
}
.main>div {
    float: left;
}

.left {
    width: 100px;
    background: red;
    margin-left: -100%;
}

.right {
    width: 100px;
    background: blue;
    margin-left: -100px;
}

.middle {
    width: 100%;
    background: yellow;

}

.content {
    margin-left: 100px;
    margin-right: 100px;
}