var limit = 500;
$(document).ready(
function()
{
	$("form[name=formularz] textarea[name=uwagi]").keyup(
	function()
	{
		var count_chars = $(this).val().length;
		if (count_chars > limit)
		{
			var new_value = $(this).val().substring(0, limit);
			$(this).val(new_value)
		}
		$("#countChars span").html(""+limit - $(this).val().length+"");
	});

});