为什么没有设置引导选项？

Question

我正在尝试为内容可编辑的 div 提供某些属性的运行时选项，并使用 JS 来显示它。为了测试，我提供了一些数据属性。

HTML 表单：

<form id="form-email-preview" style="margin-top: 24px;">
    <div id="main-container" class="hidden" style="border: 1px solid orange; padding: 6px;  border-radius: 8px;">
        <div id="subject-container" class='hidden' style="display: inline; padding-left: 4px;">
            <span>Subject: </span><input id="subject" type="text" value="Manuscript Request" />
        </div>
        <div id="mail-container" contenteditable data-toggle="popover" data-trigger="focus" data-placement="right" data-title ="Required field" style="display: inline-block"></div><br/>
        <p id="buttons" class="hidden">
            <input type='button' id='send-email' class='btn btn-custom-success' value='Send Email' /><span>   </span>
            <button id='cancel-email' class = 'btn btn-danger'>Cancel</button>
        </p>
    </div>
    <div id="current-row" class="hidden"></div>
    <input id="current-checkbox" type="checkbox" class="hidden" />
    <input id="current-tr" type="number" class="hidden" />
</form>

虽然弹出框确实显示了 data -props，但不显示运行时选项。

JavaScript

$('[data-toggle=popover]').popover();

,,,

$("#send-email").on('mousedown', function (e) {
//$("#form-email-preview").on('submit', function (e) { //doesn't fire?
//    e.preventDefault();
    var mc = $("#mail-container");
    //debugger
    if (!$.trim(mc.val())) {
        mc.popover({content: 'Please fill in this field.', placement: 'top', trigger: 'focus'});
        mc.popover('show');
        mc.focus();
        return false;
    }
    var data = {};
    data.action = "manuscript-request-email";
    data["writers-id"] = $("#writer-id").val();
    data["account-id"] = localStorage.getItem("account-id");
    data.subject = $("#subject").val();
    data.body = $("#mail-container").html();
    ajax('post', 'php/writers.php', data, sentEmail);
    function sentEmail(result) {
        console.log("email-res=" + result);
        return2table();
    }
});

我错过了什么？

Answer 1

经过数小时的搜索和实验，以下内容对我有用：

    var mc = $("#mail-container");
    if (!$.trim(mc.text())) {
        mc.popover("destroy").popover({ content: "Please fill out this field", placement: 'right' });
        mc.popover('show');
        mc.focus();
        return false;
    }