Libary-less addClass and removeClass functions

gistfile1.js

function addClass(elem, newClass) {
  var curClass = elem.className;
  if(!new RegExp(newClass,'i').test(curClass)){
    if(curClass.length > 0 && curClass.charAt(curClass.length) === '') {
       newClass = ' ' + newClass;
    }
    elem.className += newClass;
  }
};

function removeClass(elem, cssClass) {
  elem.className = elem.className.replace(' ' + cssClass,'');
};