w3schools js options code example

Example 1: options in html

<form id="form">
            <label for=""></label>
            <br>
            <input type="" id="">
            <br>
            <label for=""></label>
            <br>
            <input list="browsers" name="Thenicknamey" id="Thenickname">
            <datalist id="browsers">
                <option value=""></option>
                <option value=""></option>
                <option value=""></option>
            </datalist>
            <br>
            <label for=""></label>
            <br>
            <input type="" id="">
            <br>
            <input type="" id="">
        </form>

Example 2: javascript option

/* assuming we have the following HTML
<select id="s">
    <option>First</option>
    <option>Second</option>
    <option>Third</option>
</select>
*/ 

var s = document.getElementById('s');
var options = [ 'zero', 'one', 'two' ];

options.forEach(function(element, key) {
  if (element == 'zero') {
    s[s.options.length] = new Option(element, s.options.length, false, false);
  }                
  if (element == 'one') {
    s[s.options.length] = new Option(element, s.options.length, true, false); // Will add the "selected" attribute    
  }
  if (element == 'two') {
    s[s.options.length] = new Option(element, s.options.length, false, true); // Just will be selected in "view"
  }
});

/* Result
<select id="s">
  <option value="0">zero</option>
  <option value="1" selected="">one</option>
  <option value="2">two</option> // User will see this as 'selected'
</select>
*/