$(document).ready(function() {		
			$("#product").change(function() {
				var sel = $(this).val();
				if(sel == "koloved" || sel == "dinimveod" || sel == "kolmas" || sel == "kolatid" || sel == "takdinw")
				{							
					$(".hide_ets").css("display","none");					
					$(".hide_etw").css("display","block");
					$(".hide_browsers").show();	
					<?php $_SESSION['empty'] = 1; ?>
					$("#error_id").val("<?php echo $_SESSION['empty']; ?>");
				}
				else
				{					
					$(".hide_ets").css("display","block");					
					$(".hide_etw").css("display","none");
					$(".hide_browsers").hide();	
					<?php $_SESSION['empty'] = 0; ?>
					$("#error_id").val("<?php echo $_SESSION['empty']; ?>");
				}
});