我刚刚开始学习如何使用 javascript，它是我的第一语言。 我想做的是让每个单选按钮从输入金额中减去一个金额。目前它仅适用于 1 个单选按钮。如果我点击 2，它只会从底部的一个中减去。
<!doctype html>
<html lang="en">
<head>
<meta charset="utf-8">
<title>Numbers Test</title>
</head>
<body>
<form name="operation_form">
<label>Verify</label>
<br/>
<label>Acert Score:</label><input type="number" name='acertscore' />
<br/>
<input type="radio" name="rad1" id="rad1" value='-100' />100
<br/>
<input type="radio" name="rad2" id="rad2" value='-200' />200
<br/>
<input type="radio" name="rad3" id="rad3" value='-250' />250
<br/>
<input type="button" value="Calculate" onclick="operationForm();" />
<br/>
<label>Score total is:</label><input type="text" name="answerbox">
<br/>
<input type="button" value="Reset" onClick="this.form.reset()" />
</form>
<script type="text/javascript">
function operationForm() {
var form = document.forms["operation_form"];
var x = form["acertscore"].value;
var operation = null;
var answer = null;
if (form["rad1"].checked == true) {
answer = x - 100;
}
if (form["rad2"].checked == true) {
answer = x - 200;
}
if (form["rad3"].checked == true) {
answer = x - 250;
}
form["answerbox"].value = answer;
}
</script>
</body>
</html>我确信我的做法是错误的。如果有更简单的方法我很想学习。
最佳答案
每次您碰巧看到已检查的表单输入时，您都会将 Acert 分数的答案设置为减去单选按钮的值，从而每次都会有效地覆盖它。
另外 - 您使用单选按钮而不是复选框有什么原因吗？您不必在表单上有重置按钮。
<!doctype html>
<html lang="en">
<head>
<meta charset="utf-8">
<title>Numbers Test</title>
</head>
<body>
<form name="operation_form">
<label>Verify</label>
<br/>
<label>Acert Score:</label><input type="number" name='acertscore' />
<br/>
<input type="checkbox" name="rad1" id="rad1" value='-100' />100
<br/>
<input type="checkbox" name="rad2" id="rad2" value='-200' />200
<br/>
<input type="checkbox" name="rad3" id="rad3" value='-250' />250
<br/>
<input type="button" value="Calculate" onclick="operationForm();" />
<br/>
<label>Score total is:</label><input type="text" name="answerbox">
<br/>
<input type="button" value="Reset" onClick="this.form.reset()" />
</form>
<script type="text/javascript">
function operationForm() {
var form = document.forms["operation_form"];
var x = form["acertscore"].value;
var operation = null;
var answer = null;
if (form["rad1"].checked === true) {
x -= 100;
}
if (form["rad2"].checked === true) {
x -= 200;
}
if (form["rad3"].checked === true) {
x -= 250;
}
answer = x;
form["answerbox"].value = answer;
}
</script>
</body>
</html>关于javascript - 单选按钮在选中时从总数中减去，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/44813110/