Question

这是javascript代码

<script type="text/javascript">
  function Choose() {
    var n1, Price, Stock;
    n1 = document.getElementById("product").value;
    if (n1 == "1")
      Price = 12.5;
    Stock = 15;
    else
      Price = "40";
    Stock = "5";

    document.getElementById("price") = Price;
    document.getElementById("stock") = Stock;
  }

< /script

HTML正文

<select id="product"><option value="1" >PRODUCT 1</option>

PRODUCT 2

 <input type="text" value="0" id="price">

 <input type="text" value="0" id="stock">

我需要帮助！为什么这段代码不起作用？我的失败在哪里？

Answer 1

您需要设置DOM元素的值

document.getElementById("price").value = Price;
document.getElementById("stock").value = Stock;

您需要将DOM元素的属性value而不是DOM元素本身设置为整数值

此外，您在if-else块周围缺少{}。我假设您错过了>运算符，而关闭脚本标记是一个拼写错误而不是原始代码。如果它在原始代码中也改变它

<script type="text/javascript">
  function Choose() {
    var n1, Price, Stock;
    n1 = document.getElementById("product").value;
    if (n1 == "1") {
      Price = 12.5;
      Stock = 15;
    }
    else {
      Price = "40";
     Stock = "5";
    }
    document.getElementById("price").value = Price;
    document.getElementById("stock").value = Stock;
  }

< /script>

＆＃13;

 function Choose() {
     var n1, Price, Stock;
     n1 = document.getElementById("product").value;
     if (n1 == "1") {
         Price = "12.5";
         Stock = "15";
     } else {
         Price = "40";
         Stock = "5";
     }
     document.getElementById("price").value = Price;
     document.getElementById("stock").value = Stock;
 }

＆＃13;

<select id="product">
   <option value="1" >Product1</option>
   <option value="2">Product2</option>
</select>
<input type="button" value="Submit" onClick="Choose()">
<input type="text" id="price"/>
<input type="text" id="stock"/>

＆＃13;

Answer 2

<script type="text/javascript">
  function Choose(){
    var n1,Price,Stock ;
    n1 = document.getElementById("product").value;
    if (n1 == "1") {
      Price = 12.5;
      Stock = 15;
    } 
    else { 
      // place it in block
      Price = "40";
      Stock = "5";
    } // place it in block    

    document.getElementById("price").value = Price;
    document.getElementById("stock").value = Stock;
  }    
</script>

假设你得到的错误是错误的。如果在条件或循环下写入多个语句，则必须将其作为块

Answer 3

首先，情况可能并非如此，但您缺少脚本的结束标记。

</script>

其次，你也缺少if和else语句的括号。

            if (n1=="1"){
                  Price=12.5;
                  Stock=15;
            }
             else{
                  Price="40";
                  Stock="5";
             }

希望它有所帮助！

BR， JoséSousa

Javascript没有语法错误

3 个答案: