JavaScript Получите атрибут
//HTML
//<div id="elem" data-id="4hJ3s"></div>
var elem = document.getElementById("elem");
elem.getAttribute("data-id"); // "4hJ3s"
TC5550
//HTML
//<div id="elem" data-id="4hJ3s"></div>
var elem = document.getElementById("elem");
elem.getAttribute("data-id"); // "4hJ3s"//For <button name="myname"></button>
button.getAttribute("name");