get data attributes in JavaScript code

Question

I have next html:

<span data-typeId="123" data-type="topic" data-points="-1" data-important="true" id="the-span"></span>

Is it possible to get the attributes that beginning with data-, and use it in the JavaScript code like code below? For now I get null as result.

document.getElementById("the-span").addEventListener("click", function(){
    var json = JSON.stringify({
        id: parseInt(this.typeId),
        subject: this.datatype,
        points: parseInt(this.points),
        user: "H. Pauwelyn"
    });
});

Answer 1

You need to access the dataset property:

document.getElementById("the-span").addEventListener("click", function() {
  var json = JSON.stringify({
    id: parseInt(this.dataset.typeid),
    subject: this.dataset.type,
    points: parseInt(this.dataset.points),
    user: "Luïs"
  });
});

Result:

// json would equal:
{ "id": 123, "subject": "topic", "points": -1, "user": "Luïs" }

Answer 2

Because the dataset property wasn't supported by Internet Explorer until version 11, you may want to use getAttribute() instead:

document.getElementById("the-span").addEventListener("click", function(){
  console.log(this.getAttribute('data-type'));
});

Dataset documentation

getAttribute documentation

Answer 3

You can access it as

element.dataset.points

etc. So in this case: this.dataset.points

Answer 4

if you are targeting data attribute in Html element,

document.dataset will not work

you should use

document.querySelector("html").dataset.pbUserId

or

document.getElementsByTagName("html")[0].dataset.pbUserId

Answer 5

Try this instead of your code:

var type=$("#the-span").attr("data-type");
alert(type);