Text Area Max Length by Word Count implemented with Javascript

maxlength.js

// TO DO
// Removes the last space input by user

// Ensure code runs after form is loaded
window.onload = function() {
 
  // Main function
  function maxLength(el, max) {
    el.onkeyup = function() {
      var charLength = el.value.length;
      var wordLength = el.value.split(" ").length;
      if (wordLength == max) {
        el.setAttribute("maxlength", charLength+1);
      } else if (wordLength > max) {
        el.value.split(" ").slice(0, max).join(" ");
      }
    }
  }

  // Function call for element by data- attribute without value
  maxLength(document.querySelector("[data-attribute]"), 10);
  // Function call for element by data- attribute with value
  maxLength(document.querySelector("[data-attribute='value']"), 10);
  // Function call for element by class
  maxLength(document.getElementByClassName("class"), 10);
  // Function call for element by id
  maxLength(document.getElementById("id"), 10);
  // Function call for element by element tag
  maxLength(document.getElementByTagName("tag"), 10);

}