scripts/dom/index.js
function _setClass(el, className) {
    el instanceof SVGElement ?
        el.setAttribute('class', className) :
        el.className = className;
}
function _setClass(el, className) {
    el instanceof SVGElement ?
        el.setAttribute('class', className) :
        el.className = className;
}
function _setClass ( el , className ) { el instanceof SVGElement ? el . setAttribute ( 'class' , className ) : el . className = className ; }
Set class value of element

@private
@param {HTMLElement} el
@param {string} className
Set class value of element