Php 当我试图在确认中显示数据时，我总是得到一个未定义的

我有以下javascript和php/html代码：

<script>
          var examInput = document.getElementById('newAssessment').value;
          var dateInput = document.getElementById('newDate').value;
          var timeInput = document.getElementById('newTime').value;

         function showConfirm(){

         var confirmMsg=confirm("Are you sure you want to update the following:" + "\n" + "Exam: " + examInput +  "\n" + "Date: " + dateInput + "\n" + "Time: " + timeInput);

         if (confirmMsg==true)
         {
         submitform();   
     }
}

</script>

var TestPut=document.getElementById（'newAssessment'）。值；
var dateInput=document.getElementById（'newDate'）。值；
var timeInput=document.getElementById（'newTime'）。值；
函数showConfirm（）{
var confirmsg=confirm（“是否确实要更新以下内容：”+“\n”+”检查：“+testput+”\n”+”日期：“+dateInput+”\n”+”时间：“+timeInput”）；
如果（confirmMsg==true）
{
submitform（）；
}
}

标记在标记中遇到时立即执行。我们假设您的
标记出现在它在
getElementById（）
调用中引用的HTML之前

由于设置变量的三行出现在它们的任何函数之外，并在加载DOM之前立即执行，因此相应的DOM元素还不存在，并且变量变得
未定义
。只需将它们移动到函数中。这样做的另一个好处是，在以后调用函数时，这些值都是最新的

 function showConfirm(){
   // Load these variables inside the function
   // If placed outside, their DOM nodes are not yet loaded when the script runs
   var examInput = document.getElementById('newAssessment').value;
   var dateInput = document.getElementById('newDate').value;
   var timeInput = document.getElementById('newTime').value;

   var confirmMsg=confirm("Are you sure you want to update the following:" + "\n" + "Exam: " + examInput +  "\n" + "Date: " + dateInput + "\n" + "Time: " + timeInput);

   if (confirmMsg)
   {
     submitform();   
   }
 }

当你先回答时，你会得到最好的答案：）
 function showConfirm(){
   // Load these variables inside the function
   // If placed outside, their DOM nodes are not yet loaded when the script runs
   var examInput = document.getElementById('newAssessment').value;
   var dateInput = document.getElementById('newDate').value;
   var timeInput = document.getElementById('newTime').value;

   var confirmMsg=confirm("Are you sure you want to update the following:" + "\n" + "Exam: " + examInput +  "\n" + "Date: " + dateInput + "\n" + "Time: " + timeInput);

   if (confirmMsg)
   {
     submitform();   
   }
 }