如何从输入字段中获取数字值? [英] How to get a number value from an input field?
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问题描述
在使用JS计算某些内容并从输入字段(数字)中获取正确的值时，我遇到了一些问题.当我使用此代码时，它什么也不会显示.那么我的JS有什么问题呢?我需要包括一个jQuery文件吗?
I have some issues with calculating some stuff with JS and getting the right values out of the input fields (number). When I use this code it doesn't show anything. So what is wrong with my JS? Do I need to include a jQuery file?
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<html>
<head>
</head>
<body>
<form id="frm1" action="Calculate.html">
<table width="350px" border="1px">
<tr>
<th colspan="2">Availability</th>
</tr>
<tr>
<td>Total Production Time</td>
<td><input type="number" name="TotalProductionTime" placeholder=""> hours</td>
</tr>
<tr>
<td>Breaks</td>
<td><input type="number" name="Breaks" placeholder=""> minutes</td>
</tr>
<tr>
<td>Malfunctions</td>
<td><input type="number" name="Malfunctions" placeholder=""> minutes</td>
</tr>
<tr>
<td>Theoretical production time:</td>
<td><p id="test"></p></td>
</tr>
</table>
<input type="button" onclick="Calculate()" name="Calculate" value="calculate">
<script>
function Calculate()
{
var TotalProductionTime = document.getElementById("TotalProductionTime").value;
var TotalProductionTimeInMinutes = TotalProductionTime * 60;
var Breaks = document.getElementById("Breaks").value;
var Malfunctions = document.getElementById("Malfunctions").value;
var TheoreticalProductionTime = TotalProductionTimeInMinutes - Breaks - Malfunctions;
document.getElementById("test").innerHTML = TheoreticalProductionTime;
}
</script>
</body>
</html>
推荐答案
您在HTML中遇到了一些错误，但这是一个有效的JSFiddle:小提琴
You had some mistakes in your HTML, but here is a working JSFiddle: Fiddle
您正在尝试通过它们的ID获取元素，但是您没有给他们一个ID，而是给他们一个名称.另外，停止使用内联JavaScript调用；这是不好的做法.
You you are trying to get elements by their ID, but you don't give them an ID you give them a Name. Also, stop using inline JavaScript calls; it is bad practice.
function Calculate() {
var TotalProductionTime = document.getElementById("TotalProductionTime").value;
var TotalProductionTimeInMinutes = TotalProductionTime * 60;
var Breaks = document.getElementById("Breaks").value;
var Malfunctions = document.getElementById("Malfunctions").value;
var TheoreticalProductionTime = TotalProductionTimeInMinutes - Breaks - Malfunctions;
document.getElementById("test").innerHTML = TheoreticalProductionTime;
}
<form id="frm1" action="Calculate.html">
<table width="350px" border="1px">
<tr>
<th colspan="2">Availability</th>
</tr>
<tr>
<td>Total Production Time</td>
<td>
<input type="number" id="TotalProductionTime" placeholder="">hours</td>
</tr>
<tr>
<td>Breaks</td>
<td>
<input type="number" id="Breaks" placeholder="">minutes</td>
</tr>
<tr>
<td>Malfunctions</td>
<td>
<input type="number" id="Malfunctions" placeholder="">minutes</td>
</tr>
<tr>
<td>Theoretical production time:</td>
<td>
<p id="test"></p>
</td>
</tr>
</table>
<input type="button" onclick="Calculate()" value="calculate">
</form>
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