表单输入未保存在JavaScript函数中。 为什么？
[英]form input does not get saved in JavaScript function. Why?
问题描述
I can not find why this does not work. 
我找不到为什么这行不通。 "document.getElementById("number").value" won't "return" in function.. My HTML code: “ document.getElementById（” number“）。value”不会在函数中“返回”。我的HTML代码：
<!DOCTYPE html>
<html>
<head>
<link rel="stylesheet" type="text/css" href="Currency_Converter.css">
<link rel="stylesheet" href="http://code.jquery.com/ui/1.10.3/themes/smoothness/jquery-ui.css"/>
</head>
<body>
<div class="container">
<h1>Currency Converter</h1>
<form id="amount">Dollar amount  $<input id="number" type="number" name="number" onkeyup="getDollarAmount();" onchange="getDollarAmount();" placeholder="type dollar amount here" ></form>
</div>
</body>
<script type="text/javascript" src="http://code.jquery.com/jquery-1.9.1.js"></script>
<script type="text/javascript" src="http://code.jquery.com/ui/1.10.3/jquery-ui.js"></script>
<script type='text/javascript' src="Currency_Converter.js"></script>
</html>
My JavaScript: 我的JavaScript：
function getDollarAmount() {
var dollarAmount = document.getElementById("number").value;
return (dollarAmount);
}
console.log(getDollarAmount());
My "function getDollarAmount()" does not return the number put into the form. 我的“函数getDollarAmount（）”不返回放入表单的数字。 When I "console.log (dollarAmount)" I get my input. 当我“ console.log（dollarAmount）”时，我得到了输入。 When I take out the "document.getElementById("number").value" and replace it with a number, (ex.: 5) the "getDollarAmount" function returns the number (5). 当我取出“ document.getElementById（” number“）。value”并替换为数字时，（例如：5），“ getDollarAmount”函数将返回数字（5）。
Obviously, the issue is with "document.getElementById("number").value" since the function works in every other way. 显然，问题在于“ document.getElementById（“ number”）。value“，因为该函数以其他方式工作。 What do I need to do to get "document.getElementById("number").value" to be returned to "getDollarAmount()"? 我需要怎么做才能将“ document.getElementById（” number“）。value”返回给“ getDollarAmount（）”？
2 个解决方案
解决方案1
0 2017-04-05 14:54:54
尝试
var dollarAmount = $("#number").val();
解决方案2
0 2017-04-05 15:03:10
The mistake here is that you are returning the value instead of assigning the dollarAmount variable to the input value attribute. 这里的错误是您要返回值，而不是将dollarAmount变量分配给输入值属性。
Apart from that the idea to return the converted currency value in the same place you type the amount you want to convert to is not a good practice and will be confusing. 除此之外，在您键入要转换的金额的相同位置返回转换后的货币值的想法不是一个好习惯，而且会造成混淆。
You should have a place to input and a place to show the converted value. 您应该有一个输入位置和一个显示转换后的值的位置。 It's a better user experience and better for you. 这是更好的用户体验，对您也更好。
You don't need jQuery. 您不需要jQuery。 Here's an example: 这是一个例子：
var el = document.getElementById("number"); el.addEventListener("keyup", function() { //You need to assign the value to a variable var dollarAmount = getDollarAmount(); }); function getDollarAmount() { return el.value; }
<input id="number" type="number" name="number" placeholder="type dollar amount here" value="0" >
Hope it helps. 希望能帮助到你。
声明:本站的技术帖子网页，遵循CC BY-SA 4.0协议，如果您需要转载，请注明本站网址或者原文地址。任何问题请咨询:yoyou2525@163.com.