HTML左边盒子固定,右边盒子自适应

html:

<div class="box1">
	<div class="divA">DIVA</div>
	<div class="divB">DIVB</div>
</div>

　css:

<style type="text/css">
			* {
				margin: 0;
				padding: 0;
			}

			.box1 {
				width: 100%;
				height: 300px;
				background: #008000;
				padding:1px;
				box-sizing: border-box;
			}
			.divA {
				width: 150px;
				height: 150px;
				background: red;
				text-align: center;
				float: left;
			}

			.divB {
				margin-left: 150px;
				height: 260px;
				background: blue;
				text-align: center;
				margin-top: 20px;
			}
		</style>