说我找不到函数什么意思ReferenceError: click is not defined？

<!DOCTYPE html>
<html>
   <head>
       <meta charset="utf-8">
       <title></title>
       <style>
           *{
               margin: 0;
               padding: 0;
               list-style: none;
           }
           #box{
               width: 700px;
               height: 320px;
               margin: 200px auto;
               background-color: red;
           }
           #boxleft{
               float: left;
               width: 350px;
               height: 300px;
               /*background-color: black;*/
               padding: 50px;
           }
           #boxleft img{
               width: 300px;
               height: 200px;
               padding: 20px 8px;
               border-radius: 40%;
           }
           #boxright{
               /*background-color: purple;*/
               width: 250px;
               height: 400px;
               float: right;
           }
           #boxright #btn{
               padding: 20px 10px;
               float: left;
           }
           #boxright li{
               float: left;
               line-height: 20px;
               padding: 20px 20px;
           }
           #boxright li:nth-child(2){

               line-height: 20px;
               padding: 20px 50px;
           }
           #boxright li:nth-child(8){

               line-height: 20px;
               padding: 20px 0px 20px 50px;
           }
       </style>
       <script>
           function getobj(event){
                           if(window.event){
                               event = window.event;
                               otarget = event.srcElement ||event.otarget;
                           } return otarget;
                   }
           function click(){
                       //获取事物焦点
           var obj = getobj(event);
                       alert(obj.innerHTML);
                           /*window.location.href = "http://image.baidu.com/search/index?tn=baiduimage&word="+obj.innerHTML;*/
                       }
                       //点击事件转成百度图片

                   //鼠标进入
                   function over(){
                       obj2 = getobj(event);
                       var images = document.getElementById("photo");
                       var url = "img/"+obj2.innerHTML+"/1.jpg";
                       /*alert(url);*/
                       images.src=url;
                   }
                   //鼠标移出
                   var a=null;
                   var index=0;
               function out(){
                       var images = document.getElementById("photo");
                       clearTimeout(a);
                           index++;
                           if(index>7){index=1;}
                       var url2 = "img/"+obj2.innerHTML+"/"+"index"+".jpg";
                       images.src=url2;
                       a=setTimeout(out(),20);

                   //改变透明度
                   var op=1;
                   var change=0;
               function changeop(){

                       if(op>=1){
                           change=-0.1;
                       }else if(op>0.4){
                           change=0.1
                       }
                       op = op+change;
                       images.style.opacity="op";

                   }
       </script>
       


   </head>
   <body>
       <div id="box">
           <div id="boxleft">
               <img src="img/tu.jpg" alt="" id="photo">

           </div>
           <div id="boxright">
               <div id="btn">
                   <input type="text" />
                   <input type="button" value="搜索" style="height: 20px;" id="button"></div>
                   <div id="txt">
                       <ul>
                           <li class="thing">兵马俑</li>
                           <li class="thing">川菜</li>
                           <li class="thing">客家土楼</li>
                           <li class="thing">民族乐器</li>
                           <li class="thing">青铜重器</li>
                           <li class="thing">新疆风情</li>
                           <li class="thing">粤菜</li>
                           <li class="thing">中国国宝</li>
                       </ul>
                   </div>

           </div>
       </div>

       <script>

           //获取事件
           var things = document.getElementsByClassName("thing")
           for(var i=0;i<things.length;i++){
               things[i].addEventListener("click",click,true),
               things[i].addEventListener("mouseover",over,true),
               things[i].addEventListener("mouseout",out,true)
           }

           var images = document.getElementById("photo");
           var button = document.getElementById("button")
               console.log(button);
           button.onclick = function(){
               var text = button.value;
               if(text!==""){
                   window.location.href = "http://image.baidu.com/search/index?tn=baiduimage&word="+text;
                   }
           }

       </script>
   </body>
</html>

第一个script代码有问题。大括号不闭合，所以导致click函数没有生成

第二个问题，

a = setTimeout(out(), 20);

这句要改成

a = setTimeout(out, 20);

要不会死循环

<!DOCTYPE html>
<html>

<head>
    <meta charset="utf-8">
    <title></title>
    <style>
        * {
            margin: 0;
            padding: 0;
            list-style: none;
        }

        #box {
            width: 700px;
            height: 320px;
            margin: 200px auto;
            background-color: red;
        }

        #boxleft {
            float: left;
            width: 350px;
            height: 300px;
            /*background-color: black;*/
            padding: 50px;
        }

        #boxleft img {
            width: 300px;
            height: 200px;
            padding: 20px 8px;
            border-radius: 40%;
        }

        #boxright {
            /*background-color: purple;*/
            width: 250px;
            height: 400px;
            float: right;
        }

        #boxright #btn {
            padding: 20px 10px;
            float: left;
        }

        #boxright li {
            float: left;
            line-height: 20px;
            padding: 20px 20px;
        }

        #boxright li:nth-child(2) {

            line-height: 20px;
            padding: 20px 50px;
        }

        #boxright li:nth-child(8) {

            line-height: 20px;
            padding: 20px 0px 20px 50px;
        }
    </style>
    <!-- <script>
        function getobj(event) {
            if (window.event) {
                event = window.event;
                otarget = event.srcElement || event.otarget;
            } return otarget;
        }
        function click() {
            //获取事物焦点
            var obj = getobj(event);
            alert(obj.innerHTML);
            /*window.location.href = "http://image.baidu.com/search/index?tn=baiduimage&word="+obj.innerHTML;*/
        }
        //点击事件转成百度图片

        //鼠标进入
        function over() {
            obj2 = getobj(event);
            var images = document.getElementById("photo");
            var url = "img/" + obj2.innerHTML + "/1.jpg";
            /*alert(url);*/
            images.src = url;
        }
        //鼠标移出
        var a = null;
        var index = 0;
        function out() {
            var images = document.getElementById("photo");
            clearTimeout(a);
            index++;
            if (index > 7) { index = 1; }
            var url2 = "img/" + obj2.innerHTML + "/" + "index" + ".jpg";
            images.src = url2;
            a = setTimeout(out(), 20);

            //改变透明度
            var op = 1;
            var change = 0;
            function changeop() {

                if (op >= 1) {
                    change = -0.1;
                } else if (op > 0.4) {
                    change = 0.1
                }
                op = op + change;
                images.style.opacity = "op";

            }
    </script> -->



</head>

<body>
    <div id="box">
        <div id="boxleft">
            <img src="img/tu.jpg" alt="" id="photo">

        </div>
        <div id="boxright">
            <div id="btn">
                <input type="text" />
                <input type="button" value="搜索" style="height: 20px;" id="button">
            </div>
            <div id="txt">
                <ul>
                    <li class="thing">兵马俑</li>
                    <li class="thing">川菜</li>
                    <li class="thing">客家土楼</li>
                    <li class="thing">民族乐器</li>
                    <li class="thing">青铜重器</li>
                    <li class="thing">新疆风情</li>
                    <li class="thing">粤菜</li>
                    <li class="thing">中国国宝</li>
                </ul>
            </div>

        </div>
    </div>

    <script>


        var things = document.getElementsByClassName("thing")
        for (var i = 0; i < things.length; i++) {
            things[i].addEventListener("click", click, true),
                things[i].addEventListener("mouseover", over, true),
                things[i].addEventListener("mouseout", out, true)
        }

        var images = document.getElementById("photo");
        var button = document.getElementById("button")
        console.log(button);
        button.onclick = function () {
            var text = button.value;
            if (text !== "") {
                window.location.href = "http://image.baidu.com/search/index?tn=baiduimage&word=" + text;
            }
        }


        function getobj(event) {
            if (window.event) {
                event = window.event;
                otarget = event.srcElement || event.otarget;
            } return otarget;
        }
        function click() {
            //获取事物焦点
            var obj = getobj(event);
            alert(obj.innerHTML);
            /*window.location.href = "http://image.baidu.com/search/index?tn=baiduimage&word="+obj.innerHTML;*/
        }
        //点击事件转成百度图片

        //鼠标进入
        function over() {
            obj2 = getobj(event);
            var images = document.getElementById("photo");
            var url = "img/" + obj2.innerHTML + "/1.jpg";
            /*alert(url);*/
            images.src = url;
        }
        //鼠标移出
        var a = null;
        var index = 0;
        function out() {
            var images = document.getElementById("photo");
            clearTimeout(a);
            index++;
            if (index > 7) { index = 1; }
            var url2 = "img/" + obj2.innerHTML + "/" + "index" + ".jpg";
            images.src = url2;
            a = setTimeout(out(), 20);

            //改变透明度
            var op = 1;
            var change = 0;
            function changeop() {

                if (op >= 1) {
                    change = -0.1;
                } else if (op > 0.4) {
                    change = 0.1
                }
                op = op + change;
                images.style.opacity = "op";

            }
        }
    </script>
</body>

</html>

1.首先你写了两个script 2.其次你out（）函数少个}。