js中通过ajax调用网上接口

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>笑话</title>
    <style>
        #box{
            width: 100%;
            display: flex;
            justify-content: space-between;
        }
        #box>div{
            width: 30%;
            height: 600px;
            overflow: auto;
            border: 1px solid;
            border-radius: 10px;
            display: flex;
            flex-direction: column;
            align-items: center;
        }
        #box>div>div{
            width: 90%;
            background-color: pink;
            border-radius: 10px;
            margin: 10px 0;
        }
        #box>div>div>img{
            width: 90%;
            margin-left: 5%;
        }
    </style>
</head>
<body>
    <h1>笑话</h1>
    <button id="btn">查看详情</button>
    <div id="box">
        <div id="txt"></div>
        <div id="img"></div>
        <div id="gif"></div>
    </div>
    <script>
        function read(){
            ajax({
                type:"get",
                url:"http://route.showapi.com/341-1?showapi_appid=63668&showapi_sign=31c73b7db6b34ed59250ecb5c370b6e2",
                dataType:"json",
                success:function(responseData){
                    var data = responseData.showapi_res_body.contentlist;
                    // console.log(data);
                    var html = "";
                    data.forEach(function(txt){
                        html += `<div>
                                    <h3>${txt.title}</h3>
                                    <p>${txt.text}</p>
                                </div>`;
                    });
                    document.getElementById("txt").innerHTML = html;
 
                }
            });
            ajax({
                type:"get",
                url:"http://route.showapi.com/341-2?showapi_appid=63668&showapi_sign=31c73b7db6b34ed59250ecb5c370b6e2&page=3",
                dataType:"json",
                success:function(responseData){
                    var data = responseData.showapi_res_body.contentlist;
                    // console.log(data);
                    var html = "";
                    data.forEach(function(txt){
                        html += `<div>
                                    <h3>${txt.title}</h3>
                                    <img src="${txt.img}">
                                </div>`;
                    });
                    document.getElementById("img").innerHTML = html;
 
                }
            });
            ajax({
                type:"get",
                url:"http://route.showapi.com/341-3?showapi_appid=63668&showapi_sign=31c73b7db6b34ed59250ecb5c370b6e2&page=2",
                dataType:"json",
                success:function(responseData){
                    var data = responseData.showapi_res_body.contentlist;
                    // console.log(data);
                    var html = "";
                    data.forEach(function(txt){
                        html += `<div>
                                    <h3>${txt.title}</h3>
                                    <img src="${txt.img}">
                                </div>`;
                    });
                    document.getElementById("gif").innerHTML = html;
 
                }
            });
        }
        document.getElementById("btn").onclick = read;
        function ajax(options){
            options = options || {};
            var method = (options.type || "GET").toUpperCase(),
                url = options.url,
                queryString = null;
            if(!url)
                return;
            if(options.data){
                queryString = [];
                for(var attr in options.data){
                queryString.push(attr + "=" +options.data[attr]);
                }
                queryString = queryString.join("&");
            }
            if(method === "GET" && queryString){
                url += "?"+queryString;
                queryString = "";
            }
            var xhr = new XMLHttpRequest();
            xhr.open(method,url,true);
            if(method === "POST")
                xhr.setRequestHeader("Content-Type", "application/x-www-form-urlencoded");
            xhr.send(queryString);
            xhr.onreadystatechange = function(){
                if(xhr.readyState === 4){
                if(xhr.status === 200){
                    var data = xhr.responseText;
                    if(options.dataType === "json")
                    data = JSON.parse(data);
                    options.success && options.success(data);
                }else{
                    options.error && options.error(xhr.status);
                }
                }
            }
            }
    </script>
</body>
</html>