Programmatically choose item in select drop down

I have a drop down:

<select>
  <option value="1">1</option>
  <option value="2">2</option>
</select>

How would I select item 2 program开发者_StackOverflow中文版matically?

First get a handle on that select somehow:

var select = document.getElementsByTagName("SELECT")[0];

Then manipulate the selectedIndex property (I believe it's a zero-based index):

select.selectedIndex = 1;

If you're talking about pre-selecting an item, simply set the item as "selected" as follows:

<select>
  <option value="1">1</option>
  <option value="2" selected="selected">2</option>
</select>

If you're using plain HTML:

<option selected value="2">2</option>

If you're able to use jQuery, use the val() method:

<select id="foo"> //give it an id

$("#foo").val("2");

jQuery edition...

   $('#your_select').val('2');

<select>   
     <option value="1">1</option>   
     <option value="2" selected>2</option> 
</select>

The easiest solution is this:

<select>
     <option value="1">1</option>
     <option selected value="2">2</option>
</select>