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 functionsaddClass(document.getElementById("test"), "test");removeClass(document.getElementById("test"), "test")if(hasClass(document.getElementById("test"), "test")){//do something};