如何在按钮中的向下箭头和向上箭头之间切换？

Question

How can I show arrow up symbol in a button? Respectively, I would like it to change when clicked to arrow down. How can I do that??

I tried this but ....

<button onclick="sortTable(1)" id="up_down" type="button" class="button button2">Sort table<i class="fa fa-fw fa-sort-asc"></i></button>

Answer 1

I am using the latest font awesome documentation, I could not see fa-sort-asc so instead I use fa-sort-up .

function sortTable() {
  const ascending = false; // change the value to your sorting method to check if it's ascending or descending.
  const i = document.getElementById("up_down").getElementsByTagName("i")[0]
  i.classList.remove("fa-sort-up", "fa-sort-down");
  if (ascending) {
    i.classList.add('fa-sort-up');
    return;
  }

  i.classList.add('fa-sort-down');
}

Fiddle: https://jsfiddle.net/k6bxyps3/