Make LI have active state when input is focussed using css

Is there a way to make an <li> have an active state when an input field is focussed using CSS only? If not, any suggestions on the best way to go about achieving this?

See live demo: http://jsfiddle.net/W5LzP/

In the example, I want the background colour of the LI to stay yellow when the user clicks in the input field.

Example HTML:

<ol>
    <li>
    <label for="first_name">Your first name</label>
    <input name="first_name" placeholder="Type Y开发者_如何学Goour First Name" /></li>

    <li>
    <label for="lastt_name">Your last name</label>
    <input name="last_name" placeholder="Type Your Last Name" />
    </li>

    <li>
    <label for="email_address">Your first name</label>
    <input name="email_address" placeholder="Type Your Email Address" />
    </li>

    <li>
    <label for="country">Your country</label>
    <input name="country" placeholder="Select your country from the drop down list" />         
    </li>
</ol>

Example CSS:

ol li label{
    display:block;
}

ol li{
    margin-bottom:8px;
    background-color:#CCC;
}

ol li:hover{
    background-color:#090;
}

ol li:active{
    background-color:#FF9;
}

ol li input:focus{
    border:1px solid #99C;
    background-color:#99F;
}

CSS can only select descendants, it can't select ancestors (perhaps it should for the reason you have outlined).

You would have to use JavaScript, look at parentNode property.

var inputs = document.getElementsByTagName('input');

for (var i = 0, inputsLength = inputs.length; i < inputsLength; i++) {

    inputs[i].onfocus = function() {
        this.parentNode.className += 'active';
    }

    inputs[i].onblur = function() {
        this.parentNode.className = this.parentNode.className.replace(/\bactive\b/, '');
    }

}

jsFiddle.

Unfortunately css doesn't support parent selectors. So the only way to do it is to use javascript like the jQuery parent method.