How to write CSS in JavaScript economically? [SOLVED]

Is there any way I could style my element more economically and avoid writing so many lines for style? If I continue styling, it will be super long. Maybe import CSS from a css file?

function addClass() {
  console.log('fired');
  let container = document.createElement('div');
  container.setAttribute('class', 'container');
  container.style.width= "100px";
  container.style.height= "100px"; 
  container.style.border= "1px solid grey";
  document.body.appendChild(container);

Yes, define a class named “container” in CSS with the properties you want to style and then add the class to the element via JS.

Predefined CSS

.container {
  width: 100px;
  height: 100px;
  border: 1px solid grey;
}

JS

function addClass() {
  let container = document.createElement('div');
  container.setAttribute('class', 'container');
  document.body.appendChild(container);
}

Another option instead of the setAttribute method is to add the class to the classList.

container.classList.add('container');

They both accomplish the same thing.

Yes, that’s right. Predefined CSS works also for classes added in JS. Thanks for the clarification.