Vanilla js implementation jquery $(this).addClass('is-selected').siblings().removeClass('is-selected');

toggleClass.js

const toggleElements = document.querySelectorAll("#table tr");

toggleElements.forEach(el => {
  el.addEventListener("click", function () {
    this.classList.toggle("is-selected");
		
    // siblings
    Array.prototype.filter.call(el.parentNode.children, function (child) {
      return child !== el && child.classList.remove("is-selected");
    });
		
  });
});