appendChild 函数
<body>
<button onclick="test1()">test1</button>
<button onclick="test2()">test2</button>
<button onclick="test3()">test3</button>
<div id="div" style="border: 1px solid blue;">
<button> div1-span1 </button>
<button> div1-span2 </button>
<button> div1-span3 </button>
</div>
<div id="div2" style="border: 1px solid red;">
<button> div2-span1 </button>
<button> div2-span2 </button>
<button> div2-span3 </button>
</div>
</body>
<template id="scanInput">
<div >
模板
</div>
</template>