function randomString() {
			var chars = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXTZ";
			var string_length = 4;
			var randomstring = '';
			for (var i=0; i<string_length; i++) {
				var rnum = Math.floor(Math.random() * chars.length);
				randomstring += chars.substring(rnum,rnum+1);
			}
			return randomstring;
		}
		
		
		function addComment(formName){
		
		//alert($("#addCommentForm #clanek_id").attr('value'))

		  $.post("_modules/_diskuse/execute_add.php", {
					 
					 clanek_id:$("#addCommentForm #clanek_id").attr('value'), 
					 vlakno_id:$("#addCommentForm #vlakno_id").attr('value'), 
					 nazev:$("#addCommentForm #nazev").attr('value'), 
					 text:$("#addCommentForm #text").attr('value'), 
					 user_name:$("#addCommentForm #user_name").attr('value'), 
					 user_mail:$("#addCommentForm #user_mail").attr('value'),
					 check_captcha:$("#addCommentForm #check_captcha").attr('value')
					 
				 },
		  

			  function(html){
				//alert(html);  
				var formElem = '#'+formName+' .formError';
				var data  = html.split("@@@");
				
				if(data[0] == 'cancel'){
					fadeInFast(formElem);
					$(formElem).html(data[1])
					setTimeout(function(){
						$('#'+formName+' .formError').fadeOut();
						}, 3000);
				}
				if(data[0] == 'captcha'){
					fadeInFast(formElem);
					$('#captcha').attr('src','_captcha/captcha.php?c='+randomString())
					$('#check_captcha').attr('value','')
					$(formElem).html(data[1])
					setTimeout(function(){
						$('#'+formName+' .formError').fadeOut();
						}, 3000);
				}

				if(data[0] == 'ok'){
					fadeInFast(formElem);
					$(formElem).html(data[2])
					$('#diskuseTree').html(data[1])
					setTimeout(function(){
						disablePopup()
						}, 600);
					//slideUp_timeout('#odeslat', 1200)
				}
				
			  });	

	}