如何把html页面的js放到js文件里面

            <script type="text/javascript">
                var wrap = document.getElementById('wrap')
                var list = document.getElementById('list')
                var img = document.getElementById('img')
                var ol = document.getElementById('circle')
                var li = ol.getElementsByTagName('li')
                var left = document.getElementById('left')
                var right = document.getElementById('right')
                var num = 0;
                var timer = null;
                
                var arrUrl = ["img/t1.jpg","img/t2.jpg","img/t3.jpg","img/t4.jpg"];
                    left.onclick = function(ev){
                        num--;
                        if(num<0){
                            num = arrUrl.length-1;
                        }
                        changeImg();
                    }
                    
                    right.onclick = function (ev){
                        num++;
                        if(num>arrUrl.length-1){
                            num=0;
                        }
                        changeImg();
                    }
                        for(var i =0;i<arrUrl.length;i++){
                            li[i].index = i;
                            li[i].onclick = function(ev){
                                num = this.index;
                                changeImg();
                            }
                        }
                        
                        setTimeout(autoPlay(),1000);
                        
                        wrap.onmouseover = function(ev){
                            clearInterval(timer)
                        };
                        
                        wrap.onmouseout= autoPlay;
                        
                        function changeImg(){
                            img.src = arrUrl[num];
                                for (var i = 0; i<li.length; i++){
                                    li[i].className="";
                                }
                                li[num].className="on";
                        }
                        
                        function autoPlay(){
                            timer = setInterval(function(){
                                num++
                                num %= arrUrl.length;
                                changeImg();
                            },1500);
                        }
            </script>

引入即可

<script src="路径"></script>

你是要在js里面 写html吗