How to check if data attribute exist with plain javascript?

Question

I want to check if an HTML5 data attribute exists using plain javascript. I have tried the below code snippet, but it doesn't work.

if(object.getAttribute("data-params")==="undefined") {    //data-attribute doesn't exist } 

Answer 1

Element.getAttribute returns null or empty string if the attribute does not exist.

You'd use Element.hasAttribute:

if (!object.hasAttribute("data-example-param")) {     // data attribute doesn't exist } 

or Element.dataset (see also: in operator):

if (!("exampleParam" in object.dataset)) {     // data attribute doesn't exist } 

or even

if (!object.getAttribute("data-example-param")) {     // data attribute doesn't exist or is empty }