如何將默認值添加到動態下拉列表？

Question

我找到了關於如何制作用於選擇年份的動態下拉列表的代碼，但我不知道如何向下拉列表添加默認值，這是我在上面找到的代碼

下拉列表中的 HTML 循環選項值

HTML

<select id="year"></select>

JS

var start = 2018;
var end = new Date().getFullYear();
var options = "";
for(var year = start ; year <=end; year++){
  options += "<option>"+ year +"</option>";
}
document.getElementById("year").innerHTML = options;

我試過這樣，但它不起作用

<select id="year">
<option value=''>Year</option>    
</select>

和這個

var start = 2018;
var end = new Date().getFullYear();
var options = "<option value=''>Year</option>";
for(var year = start ; year <=end; year++){
  options += "<option>"+ year +"</option>";
}
document.getElementById("year").innerHTML = options;

我想要的結果是這樣的

<select id="year">
<option value=''>Year</option> 
<option value=''>2018</option> 
<option value=''>2017</option>   
</select>

有人知道怎么做嗎？

沒有expext會有很多答案，謝謝你們我會嘗試你的答案

Answer 1

好吧，你快到了，試試下面的代碼

 var start = 2012; var end = new Date().getFullYear(); var options = "<option value='' selected>Year</option>"; for(var year = start ; year <=end; year++){ options += "<option>"+ year +"</option>"; } document.getElementById("year").innerHTML = options;

 <select id="year"></select>

Answer 2

只需將selected屬性添加到option之一即可使其成為默認選擇的選項。

 <select> <option>1</option> <option selected>2</option> <option>3</option> </select>

 <select id="year"> </select> <script> var start = 2010; var end = new Date().getFullYear(); var options = "<option value='' selected>Year</option>"; for(var year = start ; year <=end; year++){ options += "<option>"+ year +"</option>"; } document.getElementById("year").innerHTML = options; </script>

Answer 3

嘗試這個：

 var start = 2015; var end = new Date().getFullYear(); var arrDate = function(start, end) { var count = (end - start) + 1; return Array.apply(0, Array(count)).map(function (element, index) { return index + start; }); } arrDate(start, end).forEach(function(v) { document.getElementById("year").innerHTML += "<option value='"+v+"'>"+ v +"</option>"; });

 <select id="year"> <option value=''>Year</option> </select>

Answer 4

您希望在年份下拉列表中顯示默認值。 試試下面的代碼，讓我知道這是否是你想要的！

html代碼：

<select id="year"></select>

js代碼：

var startYear = 2017;
var endYear = new Date().getFullYear();
var options = "<option selected>"+startYear+"</option>";

for(var year = start + 1; year <= end; year++){
  options += "<option>"+ year +"</option>";
}

document.getElementById("year").innerHTML = options;

Answer 5

如果我正確理解這個問題，我們想選擇當前年份。

var start = 2017;
var end = new Date().getFullYear();
var options = "<option value=''>Year</option>";

for (var year = start; year <= end; year++) {
  var selected = year === end ? " selected" : "";
  options += "<option value=\"" + year + "\"" + selected + ">"+ year +"</option>";
}
document.getElementById("year").innerHTML = options;