Javascript无法从输入中获取值
[英]Javascript can't get values from input
问题描述
I'm trying to get the values from the inputs in my form with JavaScript. 
我正在尝试使用JavaScript从表单输入中获取值。 But whenever I hit submit, I either get nothing, 0 or undefined. 但是，每当我点击提交时，我要么一无所获，要么0或未定义。 Mostly undefined. 大多是未定义的。 It doesn't seem to get any of the values. 它似乎没有任何值。
Here's the code 这是代码
<form id="ecoCalculator">
<div class="form-group">
<label for="k0">Start Kapital</label>
<input type="number" name="k0" class="form-control" id="k0">
</div>
<div class="form-group">
<label for="kn">Slut Kapital</label>
<input type="number" name="kn" class="form-control" id="kn">
</div>
<div class="form-group">
<label for="x">Rente</label>
<input type="number" name="x" class="form-control" id="x">
</div>
<div class="form-group">
<label for="n">Terminer</label>
<input type="number" name="n" class="form-control" id="n">
</div>
<div class="ecoButtons">
<input type="button" value="Udregn" class="btn btn-default" onclick="k0Eco()">
<input type="reset" value="Ryd" class="btn btn-default">
</div>
</form>
<div class="ecoResult">
<p id="ecoResult">Resultat</p>
</div>
</div>
<script type="text/javascript">
// Public Variables
var k0 = document.getElementById('k0').value();
var kn = document.getElementById('kn').value();
var x = document.getElementById('x').value();
var n = document.getElementById('n').value();
// Calculation of Initial Capital
function k0Eco() {
// Calculation
var k0Value = kn / (1 + x) ^ n;
// Show Result
document.getElementById("ecoResult").innerHTML = k0;
}
I've looked around at different questions but haven't found a solution to this yet. 我环顾了不同的问题，但尚未找到解决方案。
I've tried to change the names of the inputs, having the function only display a single value, but still no result. 我试图更改输入的名称，使该功能仅显示一个值，但仍然没有结果。
Thanks 谢谢
3 个解决方案
解决方案1
1 已采纳 2017-02-27 16:56:53
value isn't a function, it's a property. 值不是函数，而是属性。 Change 更改
var k0 = document.getElementById('k0').value()
to 至
var k0 = document.getElementById('k0').value
Your script also runs on page load, so nothing is filled yet. 您的脚本还可以在页面加载时运行，因此尚未填充任何内容。 You need to put the whole thing in a submit handler: 您需要将整个内容放入一个提交处理程序中：
document.getElementById('ecoCalculator').addEventListener('submit', function(e) {
e.preventDefault();
// your code here
});
Now remove the inline js from the button and make it type submit: 现在，从按钮中删除内联js，并使其提交：
<input type="submit" value="Udregn" class="btn btn-default" />
And remove the function in your js 并删除您的js中的函数
var k0 = document.getElementById('k0').value;
var kn = document.getElementById('kn').value;
var x = document.getElementById('x').value;
var n = document.getElementById('n').value;
// Calculation
var k0Value = kn / (1 + x) ^ n;
// Show Result
document.getElementById("ecoResult").innerHTML = k0Value;
解决方案2
0 2017-02-27 17:05:46
you need to parse the input value in int. 您需要将输入值解析为int。 for eg. 例如
// Public Variables
var k0 = parseInt(document.getElementById('k0').value);
var kn = parseInt(document.getElementById('kn').value);
var x = parseIntdocument.getElementById('x').value);
var n = parseIntdocument.getElementById('n').value);
解决方案3
0 2017-02-27 17:23:54
Use
valueinstead ofvalue().使用value代替value()。 It is a property not a function.它是属性而不是函数。 Put your variables inside your function.
将变量放入函数中。 When page loads you variables are getting the value of the inputs and there is nothing there. 当页面加载时，变量将获取输入的值，并且那里什么也没有。
function k0Eco() {
var k0 = document.getElementById('k0').value;
var kn = document.getElementById('kn').value;
var x = document.getElementById('x').value;
var n = document.getElementById('n').value;
var k0Value = kn / (1 + x) ^ n;
document.getElementById("ecoResult").innerHTML = k0Value;
}
- Put you javascript code inside
<head>tag or at least before the button.将您的javascript代码放在<head>标记内或至少在按钮之前。 When you try to fireonclick()event, your function is not created yet.当您尝试触发onclick()事件时，尚未创建函数。
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