Javascript 不计算增值税的增值税应用程序
我正在阅读《Murcah的Javascript和DOM脚本》一书。我正在学习第一个示例,它创建了一个销售税应用程序 这是我的小提琴,让我知道我做错了什么: HTMLJavascript 不计算增值税的增值税应用程序,javascript,html,Javascript,Html,我正在阅读《Murcah的Javascript和DOM脚本》一书。我正在学习第一个示例,它创建了一个销售税应用程序 这是我的小提琴,让我知道我做错了什么: HTML <!DOCTYPE html> <HTML> <HEAD> <TITLE>Sales Tax Calculator</TITLE> <link rel="stylesheet" type="tect/css" href="s
<!DOCTYPE html>
<HTML>
<HEAD>
<TITLE>Sales Tax Calculator</TITLE>
<link rel="stylesheet" type="tect/css" href="sales_tax.css" />
<script type="text/javascript" src="sales_tax.js"></script>
</HEAD>
<BODY>
<DIV id="content">
<h1>Sales Tax Calculator</h1>
<p>Enter the values below and click "Calculate".</p>
<div id="taxCalc">
<label for="subtotal">Subtotal:</label>
<input type="text" id="subtotal" />
<br/>
<label for="taxRate">Tax Rate:</label>
<input type="text" id="taxRate" />%
<br/>
<label for="salesTax">Sales Tax:</label>
<input type="text" id="salesTax" disabled="disabled" />
<br/>
<label for="total">Total:</label>
<input type="text" id="total" disabled="disabled" />
<br/>
<label> </label>
<input type="button" id="calculate" value="Calculate" />
<br/>
</div>
</DIV>
</BODY>
</HTML>
JavaScript
var $ = function (id) {
return document.getElementById(id);
}
var calculate_click = function () {
var subtotal = parseFloat($("subtotal").value);
var taxRate = parseFloat($("taxRate").value);
$("salesTax").value = "";
$("total").value = "";
if (isNaN(subtotal) || subtotal < 0) {
alert("Subtotal must be a number that is zero or more!");
} else if (isNan(taxRate) || taxRate < 0) {
alert("Tax Rate must be a number that is zero or more!");
} else {
var salesTax = subtotal * (taxRate / 100);
salesTax = parseFloat(salesTax.toFixed(2));
var total = subtotal + salesTax;
$("salesTax").value = salesTax;
$("total").value = total.toFixed(2);
}
}
window.onload = function () {
$("calculate").onclick = calculate_click;
$("subtotal").focus();
}
var$=函数(id){
返回文档.getElementById(id);
}
var计算\单击=函数(){
var小计=parseFloat($(“小计”).value);
var taxRate=parseFloat($(“taxRate”).value);
$(“销售税”)。价值=”;
$(“总额”)。价值=”;
如果(isNaN(小计)| |小计<0){
警报(“小计必须是零或更多的数字!”);
}else if(isNan(税率)| |税率<0){
警报(“税率必须是零或更多的数字!”);
}否则{
var salesTax=小计*(税率/100);
salesTax=parseFloat(salesTax.toFixed(2));
var总额=小计+销售税;
$(“销售税”)。价值=销售税;
$(“总计”).value=toFixed的总计(2);
}
}
window.onload=函数(){
$(“计算”).onclick=calculate\u click;
$(“小计”).focus();
}
您的代码有几个问题:
(1) 在JSFIDLE中,您已经在使用window.onload
,因此在左侧窗格中不需要指定onload,只需将代码包装在头部或主体中即可。另外,在JSFIDLE中不需要包含html
和head
以及所有这些内容
(2) isNan
不是一个函数。使用isNaN
更改此项:else if(isNan(taxRate)| | taxRate<0)
收件人:else if(isNaN(税率)| |税率<0)
检查这个更新的小提琴:不是最好的答案,但我在小提琴中修复了代码
var$=函数(id){
返回文档.getElementById(id);
}
var计算\单击=函数(){
var小计=parseFloat($(“小计”).value);
var taxRate=parseFloat($(“taxRate”).value);
$(“销售税”)。价值=”;
$(“总额”)。价值=”;
如果(isNaN(小计)| |小计<0){
警报(“小计必须是零或更多的数字!”);
}else if(isNaN(税率)| |税率<0){
警报(“税率必须是零或更多的数字!”);
}否则{
var salesTax=小计*(税率/100);
salesTax=parseFloat(salesTax.toFixed(2));
var总额=小计+销售税;
$(“销售税”)。价值=销售税;
$(“总计”).value=toFixed的总计(2);
}
}
$(“计算”).onclick=function(){calculate_click();};
$(“小计”).focus();
首先,您要包括脚本认为在jsfiddles服务器上的文件,如sales_tax.js感谢您清晰的说明。
var $ = function (id) {
return document.getElementById(id);
}
var calculate_click = function () {
var subtotal = parseFloat($("subtotal").value);
var taxRate = parseFloat($("taxRate").value);
$("salesTax").value = "";
$("total").value = "";
if (isNaN(subtotal) || subtotal < 0) {
alert("Subtotal must be a number that is zero or more!");
} else if (isNan(taxRate) || taxRate < 0) {
alert("Tax Rate must be a number that is zero or more!");
} else {
var salesTax = subtotal * (taxRate / 100);
salesTax = parseFloat(salesTax.toFixed(2));
var total = subtotal + salesTax;
$("salesTax").value = salesTax;
$("total").value = total.toFixed(2);
}
}
window.onload = function () {
$("calculate").onclick = calculate_click;
$("subtotal").focus();
}
var $ = function (id) {
return document.getElementById(id);
}
var calculate_click = function () {
var subtotal = parseFloat($("subtotal").value);
var taxRate = parseFloat($("taxRate").value);
$("salesTax").value = "";
$("total").value = "";
if (isNaN(subtotal) || subtotal < 0) {
alert("Subtotal must be a number that is zero or more!");
} else if (isNaN(taxRate) || taxRate < 0) {
alert("Tax Rate must be a number that is zero or more!");
} else {
var salesTax = subtotal * (taxRate / 100);
salesTax = parseFloat(salesTax.toFixed(2));
var total = subtotal + salesTax;
$("salesTax").value = salesTax;
$("total").value = total.toFixed(2);
}
}
$("calculate").onclick = function(){calculate_click();};
$("subtotal").focus();