我正在尝试根据我在下拉菜单中选择的内容计算总价;产品价格可以保持不变。
由于某些原因，代码对我不起作用，我做错了什么？
<title>Untitled Document</title>
<script type="text/jscript">
$('#quantity').change(function(){
var qty = $('#quantity').val();
var price = $('#productPrice').val();
var total = price * qty;
$("#totalprice").val(total);
});
</script>
</head>
<body>
<div class="pricesection">
<input type="hidden" id="productPrice" value="340"/>
Quantity:
<select id="quantity">
<option value="1" selected>1</option>
<option value="2">2</option>
<option value="3">3</option>
<option value="4">4</option>
<option value="5">5</option>
<option value="6">6</option>
<option value="7">7</option>
<option value="8">8</option>
<option value="9">9</option>
<option value="10">10</option>
</select>
Total: $
<input type="text" id="totalprice" value="340"/>
</div>
</body>
答案 0 :(得分：0)
select下拉列表中的值和使用javascript检索的输入字段是字符串。使用parseInt()函数将它们转换为整数：
var qty = parseInt($('#quantity').val());
var price = parseInt($('#productPrice').val());
或
var total = parseInt(price) * parseInt(qty);
另外，请将脚本类型更改为text/javascript，而不是text/jscript
答案 1 :(得分：0)
您需要在html中引用jQuery库。
尝试以下
Thread : Crashed: com.apple.main-thread
0 libobjc.A.dylib 0x181b9db90 objc_msgSend + 16
1 CoreFoundation 0x1825314a4 -[_CFXNotificationRegistrar find:object:observer:enumerator:] + 1548
2 CoreFoundation 0x182406788 _CFXNotificationPost + 368
3 Foundation 0x182e0e89c -[NSNotificationCenter postNotificationName:object:userInfo:] + 68
4 UIKit 0x18791f124 __47-[UIApplication _applicationDidEnterBackground]_block_invoke + 320
5 UIKit 0x1879ef5e4 +[UIViewController _performWithoutDeferringTransitions:] + 128
6 UIKit 0x18791ef90 -[UIApplication _applicationDidEnterBackground] + 100
7 UIKit 0x18791f514 -[UIApplication _handleApplicationDeactivationWithScene:shouldForceExit:transitionContext:completion:] + 700
8 UIKit 0x18792f990 -[UIApplication _handleApplicationLifecycleEventWithScene:transitionContext:completion:] + 448
9 UIKit 0x18791961c __70-[UIApplication scene:didUpdateWithDiff:transitionContext:completion:]_block_invoke + 152
10 UIKit 0x1879192a4 -[UIApplication scene:didUpdateWithDiff:transitionContext:completion:] + 712
11 FrontBoardServices 0x183ec77ac __FBSSERIALQUEUE_IS_CALLING_OUT_TO_A_BLOCK__ + 36
12 FrontBoardServices 0x183ec7618 -[FBSSerialQueue _performNext] + 168
13 FrontBoardServices 0x183ec79c8 -[FBSSerialQueue _performNextFromRunLoopSource] + 56
14 CoreFoundation 0x1824dd124 __CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE0_PERFORM_FUNCTION__ + 24
15 CoreFoundation 0x1824dcbb8 __CFRunLoopDoSources0 + 540
16 CoreFoundation 0x1824da8b8 __CFRunLoopRun + 724
17 CoreFoundation 0x182404d10 CFRunLoopRunSpecific + 384
18 GraphicsServices 0x183cec088 GSEventRunModal + 180
19 UIKit 0x1876d9f70 UIApplicationMain + 204
20 Trenìt! 0x1000f32e4 main (AppDelegate.swift:14)
21 libdispatch.dylib 0x181fa28b8 (Missing)
其余的看起来向我提出。
谢谢， 第
修改
这是一个片段
<title>Untitled Document</title>
<script type="text/jscript">
$('#quantity').change(function(){
var qty = $('#quantity').val();
var price = $('#productPrice').val();
var total = price * qty;
$("#totalprice").val(total);
});
</script>
</head>
<body>
<div class="pricesection">
<input type="hidden" id="productPrice" value="340"/>
Quantity:
<select id="quantity">
<option value="1" selected>1</option>
<option value="2">2</option>
<option value="3">3</option>
<option value="4">4</option>
<option value="5">5</option>
<option value="6">6</option>
<option value="7">7</option>
<option value="8">8</option>
<option value="9">9</option>
<option value="10">10</option>
</select>
Total: $
<input type="text" id="totalprice" value="340"/>
</div>
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.2.2/jquery.min.js"></script>
</body>
$('#quantity').change(function() {
var qty = $('#quantity').val();
var price = $('#productPrice').val();
var total = price * qty;
$("#totalprice").val(total);
});