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"
});
});
10 Answers
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" }
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'));
});
You can access it as
element.dataset.points
etc. So in this case: this.dataset.points
You could also grab the attributes with the getAttribute() method which will return the value of a specific HTML attribute.
var elem = document.getElementById('the-span');
var typeId = elem.getAttribute('data-typeId');
var type = elem.getAttribute('data-type');
var points = elem.getAttribute('data-points');
var important = elem.getAttribute('data-important');
console.log(`typeId: ${typeId} | type: ${type} | points: ${points} | important: ${important}`
);<span data-typeId="123" data-type="topic" data-points="-1" data-important="true" id="the-span"></span>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
Modern browsers accepts HTML and SVG DOMnode.dataset
Using pure Javascript's DOM-node dataset property.
It is an old Javascript standard for HTML elements (since Chorme 8 and Firefox 6) but new for SVG (since year 2017 with Chorme 55.x and Firefox 51)... It is not a problem for SVG because in nowadays (2019) the version's usage share is dominated by modern browsers.
The values of dataset's key-values are pure strings, but a good practice is to adopt JSON string format for non-string datatypes, to parse it by JSON.parse().
