如何检查是否在 JavaScript 和 PHP 中设置了 jQuery 属性？

Question

在此之前，让我澄清一下我是 jQuery 和 JavaScript 的新手。如果答案很明显，我很抱歉？？？？ 好的，我正在尝试创建一个页面，用户可以在其中选择日期和时间，并希望使用 JavaScript 和 PHP 来确保用户没有返回空白字段（例如没有设置日期或时间并单击提交）。我正在使用 jQuery 的 datepicker 和 Jon Thornton 的 timepicker。我成功创建了显示该字段的字段，但我不知道在 JavaScript 中调用它并进行检查的正确方法。这是我现在的代码：

    <script src="https://code.jquery.com/jquery-1.12.4.js"></script>
<script src="https://code.jquery.com/ui/1.12.1/jquery-ui.js"></script>
<link rel="stylesheet" href="//code.jquery.com/ui/1.12.1/themes/base/jquery-ui.css">
<script type='text/javascript' src='../jQuery/jonthornton-jquery-timepicker-dbdea8e/jquery.timepicker.js'></script>
<link rel='stylesheet' href='../jQuery/jonthornton-jquery-timepicker-dbdea8e/jquery.timepicker.css'>
<script>
  $( function() {
    $( "#datepicker" ).datepicker({maxDate: "+2M", dateFormat: 'yy-mm-dd'});
  } );
    $(function(){
   $('.scrollDefaultExample').timepicker({ 'scrollDefault': 'now' }); 
});
</script>

<script>
function validateForm() {
    var date = document.forms["Time_Slot"]["datePick"].value;
    var date2 = document.getElementById("datepicker");
    var main_timeSlot = document.forms["Time_Slot"]["timeSlot"].value;
    var add1 = document.forms["Time_Slot"]["additional_1"].value;
    var add2 = document.forms["Time_Slot"]["additional_2"].value;
    var add3 = document.forms["Time_Slot"]["additional_3"].value;
    var add4 = document.forms["Time_Slot"]["additional_4"].value;
    var add5 = document.forms["Time_Slot"]["additional_5"].value;
    var add1Box = document.forms["Time_Slot"]["additional_1_box"].value;
    var add2Box = document.forms["Time_Slot"]["additional_2_box"].value;
    var add3Box = document.forms["Time_Slot"]["additional_3_box"].value;
    var add4Box = document.forms["Time_Slot"]["additional_4_box"].value;
    var add5Box = document.forms["Time_Slot"]["additional_5_box"].value;
    alert("yolo");
    console.log(date);
    if (date2 == null || date == "" || date == " ") {
        alert("A date must be chosen!");
        return false;
    }
    else if (lname == null || lname == "" || lname == " ") {
        alert("The last name field should be complete!");
        return false;
    }
    else if (email == null || email == "" || email == " ") {
        alert("The email field should be complete!");
        return false;
    }
    else if (password == null || password == "" || password = " ") {
        alert("A valid password must be entered! Note: it cannot contain just a space.");
        return false;
    }
}
</script>

<form name="Time_Slot" method="POST">
    <fieldset>
        <p>Date: <input type="text" id="datepicker" name="datePick"></p>
        <p>Time: <input type="text" class="scrollDefaultExample" name="timeSlot"></p>
        <br>
        <label><input type="checkbox" name="additional_1" value="extra_1"> Additional Time Slot: <input type="text" class="scrollDefaultExample" name="additional_1_box"></label> <br><br>

        <label><input type="checkbox" name="additional_2" value="extra_2"> Additional Time Slot: <input type="text" class="scrollDefaultExample" name="additional_2_box"></label> <br><br>

        <label><input type="checkbox" name="additional_3" value="extra_3"> Additional Time Slot: <input type="text" class="scrollDefaultExample" name="additional_3_box"></label> <br><br>

        <label><input type="checkbox" name="additional_4" value="extra_4"> Additional Time Slot: <input type="text" class="scrollDefaultExample" name="additional_4_box"></label> <br><br>

        <label><input type="checkbox" name="additional_5" value="extra_5"> Additional Time Slot: <input type="text" class="scrollDefaultExample" name="additional_5_box"></label> <br><br>

        <p><input type="submit" name="submit" value="Create Available Appointments"  onclick="return validateForm()"></p>
    </fieldset>
</form>

当我点击按钮提交时，我没有收到日期未设置的警告。如果您能告诉我一个方法，将不胜感激。 提前谢谢！

Answer 1

为了更进一步，为什么不实现 jQueryValidate？ (https://jqueryvalidation.org/)

这对于你需要的东西来说有点矫枉过正当你正在实现其他验证功能时，它值得添加，但只需在输入元素中添加“必需”，它就会满足你的要求 -当您开始开发更多功能时，您会非常喜欢可用的附加功能。

<!-- include the validation script, from CDN or download -->
<script src='    http://ajax.aspnetcdn.com/ajax/jquery.validate/1.15.0/jquery.validate.min.js'></script>

<!-- On document ready, find hte form and add the validation function -->
<script>
   $.ready(function() {
         $('form[name="Time_Slot"]').validate();
   });
</script> 

<!-- In the input, add "required" -->
<input type="text" id="datepicker" name="datePick" required>

代码未经测试，但足以让您入门。