块状box自由增添且自适应屏幕
例子：
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8" />
<title>Test</title>
<style type="text/css">
body{
margin: 0px;
padding: 0px;
text-align: center;
}
.box1 {
width: 19.5%;
height: 150px;
background-color: red;
display: inline-block;
-webkit-box-sizing: border-box;
-moz-box-sizing: border-box;
box-sizing: border-box;
}
.box2 {
height: 150px;
border: 1px solid red;
}
</style>
</head>
<body>
<div class="box1">
</div>
<div class="box1">
</div>
<div class="box1">
</div>
<div class="box1">
</div>
<div class="box1">
</div>
<div class="box1">
</div>
<div class="box1">
</div>
<div class="box1">
</div>
<div class="box1">
</div>
<div class="box1">
</div>
<div class="box1">
</div>
<div class="box1">
</div>
<div class="box1">
</div>
<div class="box1">
</div>
<div class="box1">
</div>
<div class="box1">
</div>
<div class="box1">
</div>
<div class="box1">
</div>
<div class="box1">
</div>
<div class="box1">
</div>
<div class="box1">
</div>
<div class="box1">
</div>
<div class="box1">
</div>
<div class="box1">
</div>
<div class="box1">
</div>
<div class="box1">
</div>
<div class="box1">
</div>
<div class="box1">
</div>
<div class="box1">
</div>
<div class="box1">
</div>
<div class="box1">
</div>
<div class="box2">
</div>
</body>
</html>