javascript - 未捕获的 TypeError : $. get(...).then 不是函数

Question

这是我的代码..我在控制台中收到错误 Uncaught TypeError: $.get(...).then 不是一个函数..错误位于第 18 行

<button class="btn btn-primary" id="requestButton">HTTP Request</button>
<ul id="myList"></ul>
<script type="text/javascript">
    var ulElm = document.querySelector("#myList");
    var first = false;
    var chatList;
    function updateChat() {
        console.log("update Chat called");
        $.get("http://projecttester.16mb.com/makejson.php")
        .then(function(data) {//ERROR IS IN THIS LINE
            if(!first) {
                chatList = JSON.parse(data);
                chatList.forEach(function(item) {
                    var liElm = document.createElement('li');
                    liElm.innerHTML = item.Message;
                    ulElm.appendChild(liElm);
                });
</script>
</body>

Answer 1

尝试使用这个 -

<button class="btn btn-primary" id="requestButton">HTTP Request</button>
<ul id="myList"></ul>
<script type="text/javascript">
    var ulElm = document.querySelector("#myList");
    var first = false;
    var chatList;
    function updateChat() {
        console.log("update Chat called");
        $.get("http://projecttester.16mb.com/makejson.php", function(data) {
            if(!first) {
                chatList = JSON.parse(data);
                chatList.forEach(function(item) {
                    var liElm = document.createElement('li');
                    liElm.innerHTML = item.Message;
                    ulElm.appendChild(liElm);
                }
            }
        });
    }
</script>
</body>