[JS] dropdown selecteren (Opgelost)

<select id="test">
<option value="3" selected>3</option>
<option value="12">12</option>
</select>

<select id="test">
<option value="3" selected>3</option>
<option value="12">12</option>
</select>

function getTest() {
    document.getElementById('test').select = '12';
}

function getTest() {
    document.getElementById('test').select = '12';
}

<select id="test">
	<option value="0">0</option>
  <option value="1">1</option>
  <option value="2">2</option>
  <option value="3">3</option>
</select>

<script language="javascript">
	selectOption('test', 2);
	
	function selectOption(id, value)
	{
		var objSelect = document.getElementById(id);
		var arrOptions = objSelect.options;
		
		for(var i = 0; i < arrOptions.length; i++)
		{
			arrOptions[i].selected = false;
			
			if(arrOptions[i].value == value)
			{
				arrOptions[i].selected = true;
			}
		}
	}
</script>

<select id="test">
	<option value="0">0</option>
  <option value="1">1</option>
  <option value="2">2</option>
  <option value="3">3</option>
</select>
 
<script language="javascript">
	selectOption('test', 2);
 
	function selectOption(id, value)
	{
		var objSelect = document.getElementById(id);
		var arrOptions = objSelect.options;
 
		for(var i = 0; i < arrOptions.length; i++)
		{
			arrOptions[i].selected = false;
 
			if(arrOptions[i].value == value)
			{
				arrOptions[i].selected = true;
			}
		}
	}
</script>