javascript document.getElementById（）。value
[英]javascript document.getElementById().value
问题描述
Sorry, I'm newbie, 
对不起，我是新手，
<html>
<head>
<script type="text/javascript">
var x = document.getElementById('x').value;
var y = document.getElementById('y').value;
var z = x + y;
alert(z);
</script>
</head>
<body>
<input type="number" id="x" />
<input type="number" id="y" />
</body>
</html>
If my input x = 100, and y input = 200. My popup alert are 100200. 如果我的输入x = 100，y输入= 200.我的弹出警报是100200。
How to fixed this? 怎么解决这个？
thank you. 谢谢。
3 个解决方案
解决方案1
0 已采纳 2015-02-27 06:34:06
It's because the value is a string , you need to convert it to a number and then do the addition.. This should do it.. 这是因为该值是一个string ，您需要将其转换为数字，然后进行添加..这应该这样做..
<html>
<head>
<script type="text/javascript">
var x = parseInt(document.getElementById('x').value);
var y = parseInt(document.getElementById('y').value);
var z = x + y;
alert(z);
</script>
</head>
<body>
<input type="number" id="x" />
<input type="number" id="y" />
</body>
</html>
Function parseInt will convert the string to an integer number and then 100+200 will be 300. 函数parseInt会将字符串转换为整数，然后100 + 200将为300。
解决方案2
0 2015-02-27 06:34:45
Use 采用
var z = parseInt(x) + parseInt(y); var z = parseInt（x）+ parseInt（y）;
解决方案3
0 2015-02-27 06:35:19
You need to typecast variables using
parseInt(var)since they are strings.parseInt(var)对变量进行类型转换，因为它们是字符串。
<html>
<head>
<script type="text/javascript">
var x = document.getElementById('x').value;
var y = document.getElementById('y').value;
var z = parseInt(x) + pasreInt(y);
alert(z);
</script>
</head>
<body>
<input type="number" id="x" />
<input type="number" id="y" />
</body>
</html>
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