function hasClass(ele,cls) {
  return ele.className.match(new RegExp(\'(\\\\s|^)\'+cls+\'(\\\\s|$)\'));
}
 
function addClass(ele,cls) {
  if (!this.hasClass(ele,cls)) ele.className += \" \"+cls;
}
 
function removeClass(ele,cls) {
  if (hasClass(ele,cls)) {
    var reg = new RegExp(\'(\\\\s|^)\'+cls+\'(\\\\s|$)\');
    ele.className=ele.className.replace(reg,\' \');
  }
}
 
//call the functions
addClass(document.getElementById(\"test\"), \"test\");
removeClass(document.getElementById(\"test\"), \"test\")
if(hasClass(document.getElementById(\"test\"), \"test\")){//do something};