<!DOCTYPE html>
<html>
<head>
<style type="text/css">
#block1, #block2 {
 height: 20px;
 background-color: green;
}
#table {
 width: 100px;
 margin-right: auto;
}
#caption {
 height: 20px;
 background-color: blue;
}
.spacer {
 height: 30px;
}
</style>
</head>
<body>
<div id="block1"></div>
<div class="spacer"></div>
<div id="table">
 <div id="caption"></div>
</div>
<div class="spacer"></div>
<div id="block2"></div>
</body>
</html>