Uncaught Typeerror: Cannot Read Property 'Contains' of Undefined
Hi I Like to Loop Trough All "Slide" Items That Contains a Class Active and Take Their "Data-Headertext" Attribute. What Am I Doing Wrong? Var Elems =...
Hi i like to loop trough all "slide" items that contains a class active and take their "data-headertext" attribute. What am i doing wrong?
<div class="slide active"></div>
var elems = document.getElementsByClassName('slide');
for (var i = 0, len = elems.length; i < len; i++) {
if (elems.classList.contains("active")) {
myJavascriptFunc
}
}
function myJavascriptFunc() {
alert(this.getAttribute('data-headertext'));
}
1 Answer
elems in your code is a Node list which doesnot have property classList. You should access classList of element inside elems
if (elems[i].classList.contains("active"))
Simpler Way:
And also can do that using querySelectorAll() giving it multiple classes and loop using forEach()
const elems = document.querySelectorAll('.slide.active')
elems.forEach(a => console.log(a.getAttribute('data-headertext')))
In this case you want to get the data attributes. So better to use HTMLElement.dataset
`
const elems = document.querySelectorAll('.slide.active')
elems.forEach(a => console.log(a.dataset.headertext));
Maya is a hardware enthusiast who tests and reviews smart home devices, smartphones, wearables, and audio gear. She focuses on practical consumer value and build quality.
