kapustnik,
мдаа....смотрю в книгу ...
<!doctype html>
<html>
<head>
<script src="http://code.jquery.com/jquery-2.0.3.min.js"></script>
<script>
$(document).ready(function(){
$("#testlink").on("click", function() {
var weight = $('#weight').val();
alert(weight);
});
});
</script>
</head>
<body>
<input id="weight" name="weight" value="33333"></input>
<a href="#" id="testlink">testlink</a>
</body>
</html>