js封装中，用this.变量名.length作为循环条件，实现不了循环

[蒲小若]

function Slider(opt){
	this.elem = opt.dom;
	console.log(this.elem)
	this.sliders = this.elem.getElementsByClassName("banner");
//	console.log(5 < this.sliders.length);
//	this.slidersLen = this.sliders.length;

	init();
	function init(){
		renderDom();
	}
	
	function renderDom(){
		//渲染页面
		if (opt.direction == "horizontal") {
			for (var i = 0; i < this.sliders.length; i++) {
				this.sliders[i].style.position = "relative";
				this.style.top = 0;
				this.style.left = 0;
			}
		}
		
	}
	
	function bindDom(){
		//绑定事件
	}
}

window.onload = function (){
	var banner = document.getElementById("container");
	new Slider({dom:banner,direction:"horizontal"});
}

出现的问题，求大神

[天际的海浪]

function Slider(opt){
	this.elem = opt.dom;
	console.log(this.elem)
	this.sliders = this.elem.getElementsByClassName("banner");
//	console.log(5 < this.sliders.length);
//	this.slidersLen = this.sliders.length;
	var _this = this;

	init();
	function init(){
		renderDom();
	}
	
	function renderDom(){
		//渲染页面
		if (opt.direction == "horizontal") {
			for (var i = 0; i < _this.sliders.length; i++) {
				_this.sliders[i].style.position = "relative";
				_this.sliders[i].style.top = 0;
				_this.sliders[i].style.left = 0;
			}
		}
		
	}
	
	function bindDom(){
		//绑定事件
	}
}

window.onload = function (){
	var banner = document.getElementById("container");
	new Slider({dom:banner,direction:"horizontal"});
}

[斯洛文尼亚旅游]

    function Slider(opt) {
        this.elem = opt.dom;
        this.sliders = this.elem.getElementsByClassName("banner");

        this.init();
        this.init = function () {
            renderDom.call(this);
        }

        function renderDom() {
            if (opt.direction == "horizontal") {
                for (var i = 0; i < this.sliders.length; i++) {
                    this.sliders[i].style.position = "relative";
                    this.style.top = 0;
                    this.style.left = 0;
                }
            }

        }

        function bindDom() {
            //绑定事件
        }
    }

Web开发学习资料推荐
extjs开发技巧
easyui datagrid fitColumns:true失效解决办法