<!DOCTYPE html>
<html>
<head>
<style type="text/css">
#c3, #c4 {
display: none;
}
input:checked + label {
background-color: yellow;
}
</style>
<script type="text/javascript">
function toggleAllCheckboxes()
{
for (var i = 1; i <= 4; ++i) {
var cb = document.getElementById('c'+i);
cb.checked = !cb.checked;
}
}
</script>
</head>
<body onload="toggleAllCheckboxes();">
<div><input type="checkbox" name="test" id="c1"><label for="c1">check #c1</label></div>
<div><input type="checkbox" name="test" id="c2" checked><label for="c2">check #c2</label></div>
<div><input type="checkbox" name="test" id="c3"><label for="c3">check #c3</label></div>
<div><input type="checkbox" name="test" id="c4" checked><label for="c4">check #c4</label></div>
</body>
</html>