scroll滚动条插件初始化问题

var coff = true
    document.querySelector(‘#clickShowPop‘).onclick = function(){
        document.querySelector(‘.showPopWrap‘).style.display = ‘block‘;
        if(coff){
            coff = false
            new iScroll(‘.iScrollWrap4‘);
        };
    };
    document.querySelector(‘.closeBtn‘).onclick = function(){
        document.querySelector(‘.showPopWrap‘).style.display = ‘none‘;
    };