ihos, типа иллюстрация...
<!DOCTYPE html>
<html>
<head>
<script src="http://code.jquery.com/jquery-latest.js"></script>
<!--
<link rel="stylesheet" type="text/css" href="tmp.css" />
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<meta http-equiv="Content-Type" content="text/html; charset=windows-1251">
-->
<style type="text/css">
.test {
float: left;
padding: 10px;
overflow: hidden;
border: 1px solid;
}
.test.on {
border-color: red;
}
</style>
<script type="text/javascript">
$(function (){
$('.test input:text').keyup(function (){
if (this.value==0) {
$(this.parentNode).removeClass('on');
} else {
$(this.parentNode).addClass('on');
};
});
});
</script>
</head>
<body>
<div class='test'>
<input type='text' />
</div>
</body>
</html>