Using JS to implement jQuery addClass removeClass hasClass function function

Without further ado, go straight to the code

function addClass(obj, cls){

    var obj_class = obj.className,//Gets the class content.

    blank = (obj_class != '') ? ' ' : '';//
 
 
 

    added = obj_class + blank + cls;//Combine the original class with the class to be added.

    obj.className = added;//Replace the original class.

}

 

function removeClass(obj, cls){

    var obj_class = ' '+obj.className+' ';//Gets the class content and adds a space at the beginning and end.             BCD '-> 'abc              BCD '< br / >
    obj_class = obj_class.replace(/(s+)/gi, ' '),//Replace the extra empty character with a space.             BCD '-> 'ABC BCD '

    removed = obj_class.replace(' '+cls+' ', ' ');//Replace the class with a space before and after the original class. Ex) 'ABC BCD' -> 'BCD' < br / >
    removed = removed.replace(/(^s+)|(s+$)/g, '');//Ex) 'BCD' -> 'BCD' < br / >
    obj.className = removed;//Replace the original class.

}

 

function hasClass(obj, cls){

    var obj_class = obj.className,//Gets the class content.

    obj_class_lst = obj_class.split(/s+/);//
 
 

    x = 0;

    for(x in obj_class_lst) {

        if(obj_class_lst[x] == cls) {//Loop through the array to determine whether CLS 
 is included
            return true;

        }

    }

    return false;

}