<body>
<form name="frm1">
<select name="hobby" id="hobby">
<option value="">唱歌</option>
<option value="">跳舞</option>
<option value="">画画</option>
<option value="">爬山</option>
<option value="">打球</option>
</select>
</form>
<hr>
<input type="text" id="input-hobby">
<button id="btn">添加内容</button>
<script>
let select = document.querySelector("#hobby");
let selectOptionLength = select.options.length;
for(let i = 0; i < selectOptionLength; i++) {
select.options[i].value = select.options[i].textContent;
}
let btn = document.querySelector("#btn");
btn.addEventListener("click", function(event) {
let input = document.querySelector("#input-hobby");
if(input.value) {
let option = new Option(input.value, input.value);
select.appendChild(option);
网页链接 = "";
}
})
</script>
</body>