關於此標簽
<HEAD><TITLE> New Document </TITLE>
<script language="javascript" type="text/javascript">
function changeMc(a,b){
document.getElementById(a).style.display = "block"
document.getElementById(b).style.display = "none"
}
</script>
</HEAD>
<BODY>
[bo]<a href="javascript:changeMc('1','2')">层1</a>[/bo]<a href="javascript:changeMc('2','1')">层2</a>
<div id="1" style="display: block;">层1里面的内容</div>
<div id="2" style="display: none;">2相关</div>
</BODY>
請問紅色加粗字體中的href表示什麼意思呢??