The native JS uses the regular realization Removeclass hasclass Getsclass addclass.

1 function Getbyclass (oparent,sclass) {2     if(oparent.getelementsbyclassname) {3         returnoparent.getelementsbyclassname (sclass);4}Else{5         varArr=[];6         varAele=oparent.getelementsbytagname ('*');7         varRe=NewREGEXP ('\\b'+sclass+'\\b');8 9          for(varI=0; i<aele.length;i++){Ten             if(re.test (aele[i].classname)) { one Arr.push (aele[i]); a             } -         } -         returnarr; the     } - } -  -  + function Hasclass (obj,sclass) { -     varRe=NewREGEXP ('\\b'+sclass+'\\b'); +     returnre.test (obj.classname); a } at  -  - function AddClass (obj,sclass) { -     //<div class= ' ac now active ' ></div> -     //there is no class by itself -     if(obj.classname) { in         //judging the added class. -         if(!Hasclass (OBJ,SCLASS)) { toobj.classname+=' '+sclass; +         } -}Else{ theObj.classname=sclass; *     } $ }Panax Notoginseng  -  the function Removeclass (obj,sclass) { +     varRe=NewREGEXP ('\\b'+sclass+'\\b'); a     if(hasclass (OBJ,SCLASS)) { theObj.classname=obj.classname.replace (re,"'). Replace (/^\s+|\s+$/g,"'). Replace (/\s+/g,' '); +     } -}

The native JS uses the regular realization Removeclass hasclass Getsclass addclass.