toFixed 不是函数 (javascript)

Question

如果你看我最后的 javascript 行 | document.book.grandtotal.value= 总计。到固定（2）； | 在尝试运行我的代码后，它给了我一个错误，说 "grandTotal.toFixed is not a function" 如果我尝试删除 toFixed 它将正常工作。我不知道它对除此行以外的所有内容都有效

有什么问题

function calc()

{quan_1= document.book.quan1.value;
quan_2= document.book.quan2.value;
quan_3= document.book.quan3.value;
quan_4= document.book.quan4.value;
quan_5= document.book.quan5.value;
quan_6= document.book.quan6.value;
quan_7= document.book.quan7.value;

unit_1= document.book.unit1.value;
unit_2= document.book.unit2.value;
unit_3= document.book.unit3.value;
unit_4= document.book.unit4.value;
unit_5= document.book.unit5.value;
unit_6= document.book.unit6.value;
unit_7= document.book.unit7.value;

total_1= document.book.total1.value;
total_2= document.book.total2.value;
total_3= document.book.total3.value;
total_4= document.book.total4.value;
total_5= document.book.total5.value;
total_6= document.book.total6.value;
total_7= document.book.total7.value;

totalPrice1= (unit_1 * quan_1)
 document.book.total1.value=totalPrice1 .toFixed(2);
 
totalPrice2= (unit_2 * quan_2)
 document.book.total2.value=totalPrice2 .toFixed(2);
 
totalPrice3= (unit_3 * quan_3)
 document.book.total3.value=totalPrice3 .toFixed(2);
 
totalPrice4= (unit_4 * quan_4)
 document.book.total4.value=totalPrice4 .toFixed(2);
 
totalPrice5= (unit_5 * quan_5)
 document.book.total5.value=totalPrice5 .toFixed(2); 
 
totalPrice6= (unit_6 * quan_6)
 document.book.total6.value=totalPrice6 .toFixed(2); 
 
totalPrice7= (unit_7 * quan_7)
 document.book.total7.value=totalPrice7 .toFixed(2); 

 
subTotal_= (totalPrice1 + totalPrice2 + totalPrice3 + totalPrice4 + totalPrice5 + totalPrice6 + totalPrice7);
document.book.subTotal.value= subTotal_ .toFixed(2);




taxValue= document.book.county.value;
calcTax= (subTotal_ * taxValue).toFixed(2)
document.book.tax.value= calcTax;

if (document.book.county.value == "0")
    
{alert("Please select a county");}



if (subTotal_ <= 15)
{shippingCost= "5.5"}
else {shippingCost= 5.5 + (0.0450 * subTotal_)}
document.book.shipping.value= shippingCost .toFixed(2);


grandTotal = (subTotal_ + shippingCost + calcTax );
document.book.grandtotal.value= grandTotal. toFixed(2);

}

<!DOCTYPE html>
<html lang="en">



<head>
 <title>  </title>
  <meta charset="utf-8">

  <meta name="robots" content="noindex, nofollow">
  
  <script src = "dynDate.js">
  </script>
  
  <script src = "beyond14.js">
  </script>
  
  <link rel = "stylesheet" href = "beyond14.css">
  
</head>

<body>
<script language="javascript" type="text/javascript">
 document.write("<h6>Last Modified on: "+document.lastModified+"</h6>");
</script>



<main>

<center>
<table>
<form name="book" id="book">
<tr>
 <th width="180px" > Cover </th> 
 <th width="270px"> Title </th>
 <th width="200px"> Product Type </th>
 <th width="200px"> Quantity </th>
 <th width="230px"> Unit Price </th>
 <th width="200px"> Total Price </th> 
</tr>
<tr>
 <td class="align"> <img src="bk_book_woman.jpg" width="120px" height="150px" name="bookwoman" title="bookwoman"> </td>
 <td class="align"><input type="text" readonly="readonly" value="The Book Woman of Troublesome Creek" size="36"> </td>
  <td class="align"> <select size="1" name="type1" id="type1">
  <option> Audio </option>
  <option> Deck </option>
  <option> Fiction </option>
  <option> Music </option>
  <option> Non-Fiction </option>
  <option> Puzzle </option>
  <option> Reference </option>
  </select> </td>
 <td class="align"> <input type="number" size="3" name="quan1" id="quan1"> </td>
 <td class="align"> <input type="text" readonly="readonly" value="15.50" name="unit1" id="unit1"> </td>
 <td class="align"> <input type="text" readonly="readonly" name="total1" id="total1"> </td>

   
</tr> 
<tr>
 <td class="align"> <img src="au_dispatcher.jpg" width="120px" height="150px" name="" title=""> </td>
 <td class="align"><input type="text" readonly="readonly" value="The Dispatcher" size="36"> </td>
 <td class="align"> <select size="1" name="type2" id="type2">
  <option> Audio </option>
  <option> Deck </option>
  <option> Fiction </option>
  <option> Music </option>
  <option> Non-Fiction </option>
  <option> Puzzle </option>
  <option> Reference </option>
  </select> </td>
 <td class="align"> <input type="number" size="3" name="quan2" id="quan2"> </td>
 <td class="align"> <input type="text" readonly="readonly" value="12.50" name="unit2" id="unit2"> </td>
 <td class="align"> <input type="text" readonly="readonly" name="total2" id="total2"> </td>

</tr>

<tr> 
 <td class="align"> <img src="dk_gaia.jpg" width="120px" height="150px" name="" title=""> </td>
 <td class="align"><input type="text" readonly="readonly" value="Dreams of Gaia" size="36"> </td>
  <td class="align"> <select size="1" name="type3" id="type3">
  <option> Audio </option>
  <option> Deck </option>
  <option> Fiction </option>
  <option> Music </option>
  <option> Non-Fiction </option>
  <option> Puzzle </option>
  <option> Reference </option>
  </select> </td>
 <td class="align"> <input type="number" size="3" name="quan3" id="quan3"> </td>
 <td class="align"> <input type="text" readonly="readonly" value="24.99" name="unit3" id="unit3"> </td>
 <td class="align"> <input type="text" readonly="readonly" name="total3" id="total3"> </td>

</tr>

<tr> <td class="align"> <img src="bk_goldenInDeath.jpg" width="120px" height="150px" name="" title=""> </td> 
<td class="align"><input type="text" readonly="readonly" value="Golden in Death" size="36"> </td>
 <td class="align"> <select size="1" name="type4" id="type4">
  <option> Audio </option>
  <option> Deck </option>
  <option> Fiction </option>
  <option> Music </option>
  <option> Non-Fiction </option>
  <option> Puzzle </option>
  <option> Reference </option>
  </select> </td>
 <td class="align"> <input type="number" size="3" name="quan4" id="quan4"> </td>
 <td class="align"> <input type="text" readonly="readonly" value="22.50" name="unit4" id="unit4"> </td>
 <td class="align"> <input type="text" readonly="readonly" name="total4" id="total4"> </td>

</tr>

<tr> <td class="align"> <img src="bk_jefferson.jpg" width="120px" height="150px" name="" title=""> </td>
<td class="align"><input type="text" readonly="readonly" value="A Walk Down Historic Jefferson" size="36"> </td>
 <td class="align"> <select size="1" name="type5" id="type5">
  <option> Audio </option>
  <option> Deck </option>
  <option> Fiction </option>
  <option> Music </option>
  <option> Non-Fiction </option>
  <option> Puzzle </option>
  <option> Reference </option>
  </select> </td>
 <td class="align"> <input type="number" size="3" name="quan5" id="quan5"> </td>
 <td class="align"> <input type="text" readonly="readonly" value="13.50" name="unit5" id="unit5"> </td>
 <td class="align"> <input type="text" readonly="readonly" name="total5" id="total5"> </td>

</tr>

<tr>
<td class="align"> <img src="puz_millennium.jpg" width="120px" height="150px" name="" title=""> </td>
<td class="align"><input type="text" readonly="readonly" value="The New Millennium" size="36"> </td>
 <td class="align"> <select size="1" name="type6" id="type6">
  <option> Audio </option>
  <option> Deck </option>
  <option> Fiction </option>
  <option> Music </option>
  <option> Non-Fiction </option>
  <option> Puzzle </option>
  <option> Reference </option>
  </select> </td>
 <td class="align"> <input type="number" size="3" name="quan6" id="quan6"> </td>
 <td class="align"> <input type="text" readonly="readonly" value="18.95" name="unit6" id="unit6"> </td>
 <td class="align"> <input type="text" readonly="readonly" name="total6" id="total6"> </td>

</tr>

<tr>
<td class="align"> <img src="bk_signs.jpg" width="120px" height="150px" name="" title=""> </td> 
<td class="align"><input type="text" readonly="readonly" value="Signs & Symbols Sourcebook" size="36"> </td>
 <td class="align"> <select size="1" name="type7" id="type7">
  <option> Audio </option>
  <option> Deck </option>
  <option> Fiction </option>
  <option> Music </option>
  <option> Non-Fiction </option>
  <option> Puzzle </option>
  <option> Reference </option>
  </select> </td>
 <td class="align"> <input type="number" size="3" name="quan7" id="quan7"> </td>
 <td class="align"> <input type="text" readonly="readonly" value="34.95" name="unit7" id="unit7"> </td>
 <td class="align"> <input type="text" readonly="readonly" name="total7" id="total7"> </td>
  

</tr>

<tr> <td>TN County: <select size="1" name="county" id="county">
  <option value="0"> Select your county </option>
  <option value="0.0925"> Anderson </option>
  <option value="0.0875"> Cannon </option>
  <option value="0.0950"> Fayette </option>
  <option value="0.0800"> Johnson </option>
  <option value="0.0975">Williamson </option>
  </select> 

  <td colspan="3" class="alignR">  </td>
  <td class="alignR"> SubTotal: </td>
  <td class="align"> <input type="text" readonly="readonly" name="subTotal" id="subTotal"> </td> </tr>
  
<tr> 
  <td colspan="4"> &nbsp; </td>
  <td class="alignR"> S&H: </td>
  <td class="align"> <input type="text" name="shipping" id="shipping" readonly="readonly" </td> </tr>
  
<tr> 
  <td colspan="4"> &nbsp; </td>
  <td class="alignR"> Tax: </td>
  <td class="align"> <input type="text" name="tax" id="tax" readonly="readonly"> </td> </tr>
<tr> 
  <td colspan="4"> &nbsp; </td>
  <td class="alignR"> Grand Total: </td>
  <td class="align"> <input type="text" readonly="readonly" name="grandtotal" id="grandtotal"> </td> </tr>

<tr>
  <td colspan="6" class="align"> <input type="button" class="calc" value="Calculate Order" onclick="calc()"> </tr>
<tr>
  <td colspan="6" class="align"> <input type="reset" class="del" value="Cancel Order"> </tr>  
</center>
</form>
</main> 
</html>

Answer 1

首先是删除函数调用和变量之间的所有空格，我希望这只是粘贴格式问题。

然后你必须确保你正在对数字类型值调用 toFixed，所以你可以先转换为数字，以确保你没有在字符串上使用它。

所以让它像： Number(someVariable).toFixed()

Answer 2

if (subTotal_ <= 15) {shippingCost= "5.5"}

"5.5" 是字符串，不是数字。您试图将它添加到两个数字，这会将所有内容更改为一个字符串，然后对该字符串调用 toFixed()（仅适用于数字）。将 "5.5" 更改为 5.5 !

Answer 3

正如评论所述，.toFixed() 是 Number 类型的方法，而您正试图在 String 类型上使用它。因此，将您的数据转换为数字将解决该问题。这可以通过在字符串前添加 + 来最轻松地完成。这是一个例子：

var x = "5";
var y = "6";
console.log(x + y); // "56" because of string concatenation

console.log(+x + +y); // 11 because prepending a + converts string to number

toFixed 不是函数 (javascript)

toFixed is not a function (javascript)

javascript

tofixed