javascript 限制输入框只能输入数字 0-9
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Restricting an input box to only numbers 0-9
提问by John Smith
How can one restrict an inputbox to just use numbers only.
如何限制输入框只使用数字。
So if a user were to type in anything from a-z, it will not work in the inputbox.
因此，如果用户要从 az 输入任何内容，它将无法在输入框中工作。
To some this may seem easy but to me, it sounds like rocket science.
对某些人来说，这似乎很容易，但对我来说，这听起来像是火箭科学。
no jQuery please.
请不要使用jQuery。
<!DOCTYPE html>
<html>
<head>
</head>
<body>
<input type="text" id="numbersonly" />
</body>
</html>
回答by adeneo
You could use an input with the HTML5 numbertype
您可以使用 HTML5number类型的输入
<input type="number" />
or javascript, as an input with a numbertype doesn't really limitinput to numbers only :
或 javascript，作为具有number类型的输入并没有真正将输入限制为数字：
document.getElementById('numbersonly').addEventListener('keydown', function(e) {
var key = e.keyCode ? e.keyCode : e.which;
if (!( [8, 9, 13, 27, 46, 110, 190].indexOf(key) !== -1 ||
(key == 65 && ( e.ctrlKey || e.metaKey ) ) ||
(key >= 35 && key <= 40) ||
(key >= 48 && key <= 57 && !(e.shiftKey || e.altKey)) ||
(key >= 96 && key <= 105)
)) e.preventDefault();
});
