jquery ajax event.preventDefault（）取消表单的提交动作

I create a form in html:

我在html中创建一个表单:

<form id="flog" action="https://localhost/book.php" method="post">
                    <div id="inputUser">
                        <label for="userName">User</label>
                        <input type="text" name="userName" id="userName">
                    </div>
                    <div id="inputPass">
                        <label for="password">Password</label>
                        <input type="password" name="password" id="password">
                    </div>
                    <div id="savePassword">
                        <input type="checkbox" id="savePassword" value="CheckSavePAssword">Save password
                        <br>
                    </div>
                    <input type="submit" value="Acceptar">
                </form>
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