Custom HTML attributes in pure JavaScript

attributes.htm

<button type="button"
	submit-item
	data-url="/Controller/Action"
	data-item-code="ABC123">Submit ABC123</button>

<script>

//Helper to get data-items without jQuery
Object.prototype.data = function(x)
{
	if (this.dataset) { return this.dataset[x] }
	return [];
};

(document.querySelectorAll('[submit-item]')[0]).onclick = function (e) {
    e.preventDefault();
	console.log(e);
	console.log(this);
    var url = this.data("url");
    var itemCode = this.data("item-code");
    var data = {
        itemCode: itemCode
    };
    UpdateContent(url, data, function afterSend(result) {
        //Act on response
		console.log("Response", result);
    });
};

function UpdateContent(url, data, callback)
{
	//Submit to server
	console.log("Send", data, "to", url);
};

</script>