原生javascript实现分页效果

function pageFunc(conf){
 this.myFunc = conf.click //用户点击要执行的方法
 this.total = conf.total; //总页数
 this.currentPage = 1; //当前页码
 this.init()  //初始化 
}

pageFunc.prototype.init = function(){
 var total = this.total,
 currentPage = this.currentPage,
 _this = this;

 listeners = {
 'setWhat' : function(opts) {
  _this.aClick(opts.src)
  return false;
 }
 };

 listenersPre = {
 'lmw-pre' : function(opts) {
  _this.prevClick()
  return false;
 }
 };

 listenersAdd = {
 'lmw-add' : function(opts) {
  _this.addClick()
  return false;
 }
 };

 var rootele = this.createPage(1,total);
 document.getElementById('page-coat').innerHTML = rootele

 $on(document.getElementById('page-coat'), ['click'], listeners);//点击a标签
 $on(document.getElementById('page-coat'), ['click'], listenersPre);//点击上一页
 $on(document.getElementById('page-coat'), ['click'], listenersAdd);//点击下一页

}
//创建HTML分页结构字符串
pageFunc.prototype.createPage = function(page,total){
 var str = `${page}`
 for(var i=1;i<=3;i++){
 if(page-i>1){
  str = `${page-i}`+str
 }
 if(page+i${(page+i)}`
 }
 };
 if(page-4>1){
 str = '...'+str
 };
 if(page+4...'
 };
 if(page>1){
 str = `上一页1`+str
 };
 if(page${total}下一页`
 };
 return str
}
//上一页方法
pageFunc.prototype.prevClick = function(){
 var total = this.total
 var va = --this.currentPage 
 var newret = this.createPage(va, total)
 document.getElementById('page-coat').innerHTML = newret
 this.myFunc(va) 
}
//下一页方法
pageFunc.prototype.addClick = function(){
 var total = this.total
 var va = ++this.currentPage
 var newret = this.createPage(va, total)
 document.getElementById('page-coat').innerHTML = newret 
 this.myFunc(va) 
};
//点击方法
pageFunc.prototype.aClick = function(_this){
 var total = this.total
 var va = parseInt(_this.innerText);
 this.currentPage = va
 var rootele = this.createPage(va, total)
 document.getElementById('page-coat').innerHTML = rootele
 this.myFunc(va) 
};


//二：封装事件代理方法
function $on(dom, event, listeners) {
 $addEvent(dom, event, function(e) {
 var e = e || window.event,
 src = e.target || e.srcElement,
 action,
 returnVal;
 
 while (src && src !== dom) {
 action = src.getAttribute('attr-action') || src.getAttribute('class') ;
 if (listeners[action]) {
 returnVal = listeners[action]({
 src : src,
 e : e,
 action : action
 });

 if (returnVal === false) {
 break;
 }
 }
 src = src.parentNode;
 }
 });
};
//1、封装跨浏览器事件绑定方法
function $addEvent(obj, type, handle) {
 if(!obj || !type || !handle) {
 return;
 }

 if( obj instanceof Array) {
 for(var i = 0, l = obj.length; i