为了只允许在输入中写入数字和点，我们必须获取按下键的值并将其与 REGEX（test() 方法）进行比较，否则不会执行事件。
const input = document.getElementById("numberInput");
input.addEventListener("keypress", e => {
// If the input is empty and the key pressed is "0" nothing is printed
if (!e.target.value && e.key == 0) {
e.preventDefault();
} else {
// If the key pressed is not a number or a period, nothing is printed
if (!/[0-9.]/.test(keyValue)) {
e.preventDefault();
}
}
}
我还创建了一个函数，允许写入最多三个整数和两个十进制数。我希望它对你有帮助。
我通常在我的推特 ( @PabloAndresValC )上发布对我有帮助的信息或一些解决方案
input.addEventListener("keypress", e => {
const keyValue = e.key;
// If the input is empty and the key pressed is "0" nothing is printed
if (!e.target.value && keyValue == 0) {
e.preventDefault();
} else {
// If the key pressed is not a number or a period, nothing is printed
if (!/[0-9.]/.test(keyValue)) {
e.preventDefault();
} else {
// If the number has one or two whole numbers and a point, another
// point won't be printed
if (/[0-9]{1,2}[.]/.test(e.target.value) && keyValue == ".") {
e.preventDefault();
}
// If the number has one or two whole numbers and a point
else if (/[0-9]{1,2}[.]/.test(e.target.value)) {
// We can write up to two more numbers after the point
if (/[0-9]{1,2}[.][0-9]{2}/.test(e.target.value)) {
e.preventDefault();
}
}
// If there are 3 numbers and we press another, a point
// will be printed automatically
// And we can write up to two more numbers after the point
else if (/[0-9]{3}/.test(e.target.value) && keyValue != ".") {
e.target.value += ".";
if (/[0-9]{3}[.][0-9]{2}/.test(e.target.value)) {
e.preventDefault();
}
}
}
}
});