我想知道如何检测错误的输入类型,而不是向用户显示 NaN,而是显示一条逻辑信息。
这是我的代码:
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Quadratic Root Finder</title>
<script>
window.onload = function() {
document.getElementById('calculate').onclick = function calculateQuad()
{
var inputa = document.getElementById('variablea').value;
var inputb = document.getElementById('variableb').value;
var inputc = document.getElementById('variablec').value;
root = Math.pow(inputb,2) - 4 * inputa * inputc;
root1 = (-inputb + Math.sqrt(root))/2*inputa
root2 = (-inputb + Math.sqrt(root))/2*inputa
document.getElementById('root1').value = root1;
document.getElementById('root2').value = root2;
if(root<'0')
{
document.getElementById('root1').value = 'No real solution'
document.getElementById('root2').value = 'No real solution'
}
else {
if(root=='0')
{
document.getElementById('root1').value = root1
document.getElementById('root2').value = 'No Second Answer'
}
else {
document.getElementById('root1').value = root1
document.getElementById('root2').value = root1
}
}
};
document.getElementById('erase').onclick = function()
{
document.getElementById('form1').reset();
}
}
</script>
<style>
#container
{
text-align: center;
}
</style>
</head>
<body>
<div id="container">
<h1>Quadratic Root Finder!</h1>
<form id="form1">
a:<input id="variablea" value="" type="text">
<br/>
b:<input id="variableb" value="" type="text">
<br />
c:<input id="variablec" value="" type="text">
<br />
<input id="calculate" value="Calculate!" type="button">
<input id="erase" value="Clear" type="button">
<br />
<br />
Roots:
<br />
<input id="root1" type="text" readonly>
<br />
<input id="root2" type="text" readonly>
</form>
</div>
</body>
</html>
因此,假设您在b
输入字段中输入 10a,但a = 1
我c = 0
希望能够检测到不正确的输入,并打印“请仅输入整数”或类似的内容。