因为这正是规范所规定的。数字输入可以接受浮点数，包括负号和e或e字符(其中指数是e或e后面的数字):

A floating-point number consists of the following parts, in exactly the following order: Optionally, the first character may be a "-" character. One or more characters in the range "0—9". Optionally, the following parts, in exactly the following order: a "." character one or more characters in the range "0—9" Optionally, the following parts, in exactly the following order: a "e" character or "E" character optionally, a "-" character or "+" character One or more characters in the range "0—9".

<input type="number" onkeydown="javascript: return ['Backspace'，'Delete'，'ArrowLeft'，'ArrowRight'].includes(event.code) ?isNaN(Number(event.key)) && event.code!= =‘空间’" / >

角;与IDE keyCode弃用警告

功能上与rinku的答案相同，但有IDE警告预防

numericOnly(event): boolean {
    // noinspection JSDeprecatedSymbols
    const charCode = (event.which) ? event.which : event.key || event.keyCode;  // keyCode is deprecated but needed for some browsers
    return !(charCode === 101 || charCode === 69 || charCode === 45 || charCode === 43);
}

HTML输入数字类型允许“e/ e”，因为“e”代表指数，这是一个数字符号。

例200000也可以写成2e5。我希望这能帮到你，谢谢你的问题。

如果你按下一个键，它的计算机语言相当于69，它就不会输入

<input
 type="number"
 onkeydown="return event.keyCode !== 69"
/>

我们可以像下面这样简单

<input type="number" onkeydown="javascript:返回事件。keyCode == 69 ?/> . False: true

更新后的答案

我们可以让它更简单，就像@88 MPG建议的那样

<输入类型=“编号”=“回归事件”。键盘代码!