Uncaught TypeError：無法讀取未定義的屬性'naam'

Question

我在JS中進行調查，我試圖通過每次選擇第一個選項來顯示在我的頁面上的「kaas」，但它給了我這個錯誤：

「遺漏的類型錯誤：無法讀取的未定義的屬性‘NAAM’」

我該如何解決這個問題？

document.write('<form id="form" name="enquete"><p>Zoekt u naar een mobiel product of naar een alles-in-1 pakket?</p><input type="radio" name="naam" id="1">Een mobiel pakket<br><input type="radio" name="naam" id="2">Een alles in 1 pakket<br><input type="radio" name="naam" id="3">Beide<br><br><input type="button" onclick="functie()" value="Submit"></form>'); 

    function functie() 
    { 
     var Instap = 0; 
     var Standaard = 0; 
     var Premium = 0; 
     var Internet = 0; 
     var ZInstap = 0; 
     var ZStandaard = 0; 
     var ZPremium = 0; 
     var Budget100 = 0; 
     var Budget300 = 0; 
     var Basis = 0; 
     var VInternetInstap = 0; 
     var VInternetStandaard = 0; 

     document.getElementById('form').submit(); 
      for (var i = 0; i < document.enquete.naam.length; i++) 
      { 
       if (document.enquete.naam[i].checked) 
       { 
        switch(i) 
        { 
         case 0: 
         { 
         //Mobiel pakket 
         document.write('<form id="form2" name="enquete2"><p>Hoeveel belminuten wilt u per maand?</p><input type="radio" name="naam2" id="1">100<br><input type="radio" name="naam2" id="2">150<br><input type="radio" name="naam2" id="3">200<br><input type="radio" name="naam2" id="4">300<br><input type="radio" name="naam2" id="5">Onbeperkt<br><br><input type="button" onclick="" value="Submit"></form>'); 
         //document.getElementById('form2').submit(); 
         if (document.enquete2.naam2[i].checked) 
         { 
         switch(i) 
         { 
          case 0: 

          ZInstap = ZInstap + 1; 
          ZStandaard = ZStandaard +1; 
          ZPremium = ZPremium + 1; 
          document.write("kaas"); 
          break; 

          case 1: 

          Basis = Basis + 1; 
          VInternetInstap + 1; 
          break; 

          case 2: 

          VInternetStandaard = VInternetStandaard + 1; 
          break; 

          case 3: 

          Budget300 = Budget300 + 1; 
          break; 

          case 4: 

          ZInstap = ZInstap + 1; 
          ZStandaard = ZStandaard + 1; 
          ZPremium + ZPremium + 1; 
          break; 

         } 
         } 
         } 
         break; 
         /* 
         Standaard = Standaard + 1; 
         Premium = Premium + 1; 
         Internet = Internet + 1; 
         */ 


         case 1: 
         { 
         //Alles in 1 
         document.write("Alles in 1"); 

         break; 
         } 

         case 2: 
         { 
         //Beide 
         break; 
         } 
        } 
       } 
      } 
    } 

Answer 1

您無法按照您嘗試的方式按名稱訪問表單。用這個。

var formy = document.forms["enquete"];

，然後更改所有「名稱」標籤類的標籤。

var collection = formy.getElementsByClassName('naam')

，然後做你的中繼邏輯。

Answer 2

如果您爲所有表單元素提供唯一的ID而不是數字，則可以通過對象（點）符號訪問表單元素。

這裏有一個小例子：

document.write('<form id="form" name="enquete"><p>Zoekt u naar een mobiel product of naar een alles-in-1 pakket?</p><input type="radio" name="naam" id="naam1">Een mobiel pakket<br><input type="radio" name="naam" id="naam2">Een alles in 1 pakket<br><input type="radio" name="naam" id="naam3">Beide<br><br><input type="button" id="send" value="Submit"></form><br/><output id="outText" />'); 
 

 
// here goes the logic 
 
send.addEventListener('click', function() { 
 
\t var checkd = (form.naam1.checked) ? 
 
\t \t \t \t \t \t \t form.naam1.nextSibling.textContent : (form.naam2.checked) ? 
 
\t \t \t \t \t \t \t form.naam2.nextSibling.textContent : (form.naam3.checked) ? 
 
\t \t \t \t \t \t \t form.naam3.nextSibling.textContent : "nothing"; 
 
    outText.innerText = "checked: " + checkd; 
 
});