How can i highlights some text with greasemonkey? - greasemonkey

Question

I want select some text highlights with Greasemonkey.When I see that four radio button, Greasemonkey i need highlights my option.
Example: I want auto select label RealMadrid.
<div class="row">
<input type="radio" tabindex="3" value="answer1" name="ctl00$ContentPlaceHolder1$1" id="ContentPlaceHolder1_answer1"><label for="ContentPlaceHolder1_answer1">Bayern</label></div>
<div class="row">
<input type="radio" tabindex="4" value="answer2" name="ctl00$ContentPlaceHolder1$1" id="ContentPlaceHolder1_answer2"><label for="ContentPlaceHolder1_answer2">Barcelona</label></div>
<div class="row">
<input type="radio" tabindex="5" value="answer3" name="ctl00$ContentPlaceHolder1$1" id="ContentPlaceHolder1_answer3"><label for="ContentPlaceHolder1_answer3">RealMadrid</label></div>
<div class="row">
<input type="radio" tabindex="6" value="answer4" name="ctl00$ContentPlaceHolder1$1" id="ContentPlaceHolder1_answer4"><label for="ContentPlaceHolder1_answer4">Lyon</label></div>
</div>
Greasemonkey code: (it's checked radio , but instead i need highlight text)
is it possible ?
var labels = document.getElementsByTagName('label'); //get the labels
for (var i = 0; i < labels.length; ++i) { //loop through the labels
if (labels[i].textContent == "RealMadrid") { //check label text
labels[i].click(); //if correct text, click the label
}
}

Answer 1

Javascript:
var radioButtons = document.querySelectorAll('input[type=radio]');
for(var i = 0; i < radioButtons.length; i++) {
radioButtons[i].addEventListener('change', changeHandler, false);
}
function changeHandler(event) {
var b = event.target;
if(b.checked) {
document.querySelector('label[for=' + b.id + ']').style.background = 'yellow';
var notB = document.querySelectorAll('label:not([for=' + b.id + '])');
for(var j = 0; j < notB.length; j++) {
notB[j].style.background = '';
}
}
}
jQuery:
$(':radio').change(function() {
if($(this).is(':checked')) {
$(this).next().css('background', 'yellow');
$(':radio').not(this).next().css('background', '');
}
});
Demo