js验证只能输数字

function isNumeric(input) {
    return /^\d+$/.test(input);
}

// 使用示例
const userInput = "12345";
if (isNumeric(userInput)) {
    console.log("输入是数字");
} else {
    console.log("输入不是纯数字");
}

<input type="number" id="numberInput" />

document.getElementById('numberInput').addEventListener('keypress', function(event) {
    const charCode = event.which ? event.which : event.keyCode;
    if (charCode < 48 || charCode > 57) { // 48-57是数字键的ASCII码
        event.preventDefault();
    }
});

document.getElementById('myForm').addEventListener('submit', function(event) {
    const userInput = document.getElementById('numberInput').value;
    if (!isNumeric(userInput)) {
        alert('请输入纯数字');
        event.preventDefault(); // 阻止表单提交
    }
});

document.getElementById('numberInput').addEventListener('input', function() {
    this.value = this.value.replace(/\D/g, '');
});