Reset value of dropdown list with radio button

I need to reset the value of a dropdo开发者_高级运维wn list with a radio button. So when a certain radio button is selected, it will reset a specific dropdown list to the default selected="selected" option.

How can this be done with js and css?

This should reset your dropdown to the first option. Here's the markup

<select id=foo>
  <option value=""></option>
  <option value="1">1</option>
  <option value="2">2</option>
  <option value="3">3</option>
</select>
<input onclick="resetFoo();" type="radio" name="bar" value="bar">

Here's the jQuery.

function doSomething {
    $("#foo option:first").attr("selected", true);
}

Say that this is the code for your first element

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

your radio button should be something like this:

<input onclick="document.getElementById('foo').value = '';" type="radio" name="bar" value="bar">

The value under the onclick event needs to be replaced with the default value for your dropdown.

document.getElementById('select').selectedIndex = 0;

<input type="radio" onchange="doSomething()" />