See the example: https://jsfiddle.net/andreasvirkus/1ouLxxo8/1/

allcaps-capitalised.css

/* Remember to add styles for the .caps class */
.caps {
  font-size: 1.4em;
}

smallCaps.js

/* When using an all-caps font that doesn't support capitalised letter sizes, do this! */
function smallCaps() {
  var elements = document.querySelectorAll('.small-caps')

  Array.prototype.forEach.call(elements, function(e) {
    var text = e.innerHTML.toUpperCase()
    e.innerHTML = text.replace(/\b([A-Za-z0-9])/g, '<span class="caps">$1</span>')
  })
}