<!DOCTYPE html>
<html>
    <head>
        <meta charset=utf-8>
    </head>
    <body>
    	<p>1</p>
        <script type="text/javascript">
            const _elementKey = () => {
                // 补全代码
                var p = document.querySelector("p")
                //var map = new Map()
                 var map = new Map([[p, p.innerText]])
                //map.set(p, p.innerText)
                return map
            }
        </script>
    </body>
</html>