js代码

<script type="text/javascript">
	window.onload = function(){
		var btn = document.getElementById('btn');
		var cm = document.getElementById('cm');	
//				获取html中的菜单
		var menu = document.getElementsByTagName('span');
		var menuList = [];
//				遍历菜单逐个加到新菜单menuList数组中
		for(var i=0;i<menu.length;i++){
			menuList.push(menu[i].innerHTML);
		}	
		
		btn.onclick = function(){
			var num = Math.floor(Math.random()*(menuList.length-1+1-0)+0);
			cm.innerHTML = menuList[num];
		}
	}
</script>