<head>
<script>
function add()
{
Node.prototype.d = function(){
console.log(this.textContent)
};
let a = document.getElementById("a");
let b = document.getElementById("b");
a.d();
b.d();
}
</script>
</head>
<body>
<button id="btn" onclick="add()">Press </button>
<div id="a">aaaa</div>
<div id="b">bbbb</div>
</body>