<filename>assets/js/pages/input_text.js
// Input Text
// ©  Codrops
(function(window) {
  'use strict';
  // class helper functions from bonzo https://github.com/ded/bonzo
  function classReg(className) {
    return new RegExp("(^|\\s+)" + className + "(\\s+|$)");
  }
  var hasClass, addClass, removeClass;
  if ('classList' in document.documentElement) {
    hasClass = function(elem, c) {
      return elem.classList.contains(c);
    };
    addClass = function(elem, c) {
      elem.classList.add(c);
    };
    removeClass = function(elem, c) {
      elem.classList.remove(c);
    };
  }
  else {
    hasClass = function(elem, c) {
      return classReg(c).test(elem.className);
    };
    addClass = function(elem, c) {
      if (!hasClass(elem, c)) {
        elem.className = elem.className + ' ' + c;
      }
    };
    removeClass = function(elem, c) {
      elem.className = elem.className.replace(classReg(c), ' ');
    };
  }

  function toggleClass(elem, c) {
    var fn = hasClass(elem, c) ? removeClass : addClass;
    fn(elem, c);
  }
  var classie = {
    hasClass: hasClass,
    addClass: addClass,
    removeClass: removeClass,
    toggleClass: toggleClass,
    has: hasClass,
    add: addClass,
    remove: removeClass,
    toggle: toggleClass
  };
  if (typeof define === 'function' && define.amd) define(classie);
  else window.classie = classie;
  if (!String.prototype.trim) {
    (function() {
      var rtrim = /^[\s\uFEFF\xA0]+|[\s\uFEFF\xA0]+$/g;
      String.prototype.trim = function() {
        return this.replace(rtrim, '');
      };
    })();
  }
[].slice.call(document.querySelectorAll('input.input__field')).forEach(function(inputEl) {
    if (inputEl.value.trim() !== '') {
      classie.add(inputEl.parentNode, 'input--filled');
    }
    inputEl.addEventListener('focus', onInputFocus);
    inputEl.addEventListener('blur', onInputBlur);
  });
  function onInputFocus(ev) {
    classie.add(ev.target.parentNode, 'input--filled');
  }
  function onInputBlur(ev) {
    if (ev.target.value.trim() === '') {
      classie.remove(ev.target.parentNode, 'input--filled');
    }
  }
})(window);