(function () { function trimTextFields() { let selector = 'input[type=text], input[type=search], input[type=email], textarea'; let textFields = document.querySelectorAll(selector); let changeListener = function () { this.value = this.value.trim(); }; textFields.forEach( function (field, currentIndex, listObj) { field.addEventListener('change', changeListener); } ); } trimTextFields(); })();