javascript obtient un élément par classe
var elementsArray = document.getElementsByClassName("someclassname");
Grepper
var elementsArray = document.getElementsByClassName("someclassname");let elementsArray = document.getElementsByClassName("className");
// OR
let element = document.querySelector(".className");var elements = document.querySelector(".class");var elements = document.getElementsByClassName(names); // or:
var elements = rootElement.getElementsByClassName(names);let blueThings = document.getElementsByClassName('blue');
console.log(blueThings); // The HTMLCollection
console.log(blueThings[0]); // The first element with class="blue" in the document
console.log(blueThings.length); // The number of elements with class="blue" found
console.log(blueThings.item(2)); // The element at index 2 in the collection
console.log(blueThings.namedItem('specific')); // The element with both class="blue" and id="specific"var x = document.getElementsByClassName("example");
var i;
for (i = 0; i < x.length; i++) {
x[i].style.backgroundColor = "red";
}