Question

I am trying to select an option in a select menu that contains an optgroup. I have tried
document.getElementsByName("dob_year")[0].selectedIndex = "1980"; and it seems to work with select menus that contain no “optgroups”, bit it does work with them. How can I select the “1980” option?

<select name="dob_year"> 
    <optgroup label="Morning"> 
        <option value="1980">80</option> 
        <option value="1981">81</option> 
        <option value="1982">82</option> 
        <option value="1983">83</option> 
    </optgroup> 
</select> 

Answer 1

As the name suggest, the selectedIndex is an index.

So you have to use the following:

document.querySelector('select').selectedIndex = 2;

Working jsfiddle: http://jsfiddle.net/vkSKy/