为何空间已经满了,元素还会插入?
<html>
<head>
<style type="text/css">
body {
font-size:19px;
}
#box {
width:500px;
float:left;
}
#box-1 {
width:100px;
height:100px;
background-color:#FF0;
margin:10px;
float:left;
}
#box-2 {
width:100px;
height:100px;
background-color:#FF0;
margin:10px;
float:left;
}
#box-3 {
width:100px;
height:100px;
background-color:#FF0;
margin:10px;
float:left;
}
#box-4 {
width:460px;
height:50px;
background-color:#39F;
margin:10px;
}
</style>
</head>
<body>
<div id="box">
<div id="box-1">id="box-1"</div>
<div id="box-2">id="box-2"</div>
<div id="box-3">id="box-3"</div>
<div id="box-4"> id= "box-4"</div>
</div>
</body>
</html>
为何box4会插入到box1 box2 box3 里面去?已经没有位置了哈?