js input 追加属性

<input type="text" id="myInput" data-custom="value">

window.onload = function() {
    var inputElement = document.getElementById('myInput');
    inputElement.setAttribute('data-custom', 'newValue');
};

document.getElementById('someButton').addEventListener('click', function() {
    var inputElement = document.getElementById('myInput');
    inputElement.setAttribute('disabled', 'true'); // 禁用输入框
});

document.addEventListener('DOMContentLoaded', function() {
    var inputElement = document.getElementById('myInput');
    if(inputElement) {
        inputElement.setAttribute('data-custom', 'newValue');
    }
});