jQuery add blank option to top of list and make selected to existing dropdown

This worked:

$("#theSelectId").prepend("<option value="" selected='selected'></option>");

Firebug Output:

<select id="theSelectId">
  <option selected="selected" value=""/>
  <option value="volvo">Volvo</option>
  <option value="saab">Saab</option>
  <option value="mercedes">Mercedes</option>
  <option value="audi">Audi</option>
</select>

You could also use .prependTo if you wanted to reverse the order:

​$("<option>", { value: '', selected: true }).prependTo("#theSelectId");​​​​​​​​​​​