$(function() {
		// a workaround for a flaw in the demo system (http://dev.jqueryui.com/ticket/4375), ignore!
		$( "#dialog:ui-dialog" ).dialog( "destroy" );
		
		var nickname = $( "#nickname" ),
			password = $( "#password" ),
			allFields = $( [] ).add( nickname ).add( password ),
			tips = $( ".validateTips" );

		function updateTips( t ) {
			tips
				.text( t )
				.addClass( "ui-state-highlight" );
			setTimeout(function() {
				tips.removeClass( "ui-state-highlight", 1500 );
			}, 500 );
		}

		function checkLength( o, n, min, max ) {
			if ( o.val().length > max || o.val().length < min ) {
				o.addClass( "ui-state-error" );
				updateTips( "Length of " + n + " must be between " +
					min + " and " + max + "." );
				return false;
			} else {
				return true;
			}
		}

		function checkRegexp( o, regexp, n ) {
			if ( !( regexp.test( o.val() ) ) ) {
				o.addClass( "ui-state-error" );
				updateTips( n );
				return false;
			} else {
				return true;
			}
		}
		
		$( "#dialog-form" ).dialog({
			autoOpen: false,
			height: 250,
			width: 350,
			modal: true,
			draggable: false,
			resizable: false,
			buttons: {
				"Login": function() {
					var bValid = true;
					allFields.removeClass( "ui-state-error" );

					bValid = bValid && checkLength( nickname, "nickname", 3, 16 );
					bValid = bValid && checkLength( password, "password", 5, 16 );

					bValid = bValid && checkRegexp( nickname, /^[a-z]([0-9a-z_])+$/i, "Nickname may consist of a-z, 0-9, underscores, begin with a letter." );
					

					if ( bValid ) {
						 
						$( this ).dialog( "close" );
						$('#loginForm').submit();
					}
				},
				Cancel: function() {
					$( this ).dialog( "close" );
				}
			},
			close: function() {
				allFields.val( "" ).removeClass( "ui-state-error" );
			}
		});

		$( "#modal_login" )
			.button()
			.click(function() {
				$( "#dialog-form" ).dialog( "open" );
			});
	});

<div id="dialog-form" title="Login">
                <p class="validateTips">All form fields are required.</p>
            
                <form action="login.php" method="post" name="loginForm" id="loginForm">
                <fieldset>
                    <label for="nickname">Nickname</label>
                    <input type="text" name="nickname" id="nickname" class="text ui-widget-content ui-corner-all" />
                    <label for="password">Password</label>
                    <input type="password" name="password" id="password" class="text ui-widget-content ui-corner-all" />
                   
                </fieldset>
                </form>
            </div>

<?php

#session_start();

include('config.php');





//Beim Absenden des Formulars
if(isset($_POST['submit']))
{


	//Variablen werden aus dem Formular geholt
	$nickname = $_POST['nickname'];
	$pwd = $_POST['password'];
	
	//Wenn Nickname/Passwort nicht deklariert wurden, gehe zur Login-Seite
	if($nickname=="" || $pwd=="")
	{
		//echo "<div id=\"dialog-message\">Bitte geben Sie Ihre Benutzerdaten ein!</div>";
		echo "<Script>alert('Bitte geben Sie Ihre Benutzerdaten oder Passwort ein!')</script>";
		echo "<Script>history.back();</script>";
		exit();
		
	}
	
	//Ansonsten vergleiche sie mit der Datenbank
	else
	{
		$pwd_md5 = md5($pwd);
		$result = mysql_query("SELECT * FROM user WHERE nickname='$nickname' && pwd='$pwd_md5'");
		
		//Bei richtigen Daten gehe zum Useraccount
		if($result && mysql_num_rows($result)===1)
		{
			$user = mysql_fetch_array($result);
			$uid = $user['uid'];
			$visits = $user['visits'];
			//schreibe in die Datenbank
			
			mysql_query("UPDATE 
										user 
						SET 
										sessionID = '".mysql_real_escape_string(session_id())."',
                        				autologin = NULL,
                        				ip = '".$_SERVER['REMOTE_ADDR']."',
                        				last_action = '".mysql_real_escape_string(time())."',
                        				last_login = '".mysql_real_escape_string(time())."',
										visits='".($visits+1)."' 
						WHERE 
										uid= '$uid'
						");
			
			
			//such die Rechte vom eingeloggten User
			$result = mysql_query("SELECT * FROM user_rights WHERE uid='$uid'");
			$rights = mysql_fetch_array($result);
			
			/*echo "<Script>alert('".$rights['rights']."')</script>";*/
			
			$_SESSION['uid'] = $user['uid'];
			$_SESSION['nickname'] = $user['nickname'];
			$_SESSION['pwd'] = $user['pwd'];
			$_SESSION['allow_login'] = "yes";
			$_SESSION['rights'] = $rights['rights'];
			
			header("Location: ".BASEHREF."/index.php");
			exit();
		} 
			
		//Ansonten, zeige Fehlermeldung	
		else
		{
			echo "<Script>alert('Nickname oder Passwort ist falsch!')</script>";
			echo "<Script>history.back();</script>";
			exit();
		}
	}
}
else{
		echo "<Script>alert('Keine Daten gefunden!')</script>";
		echo "<Script>history.back();</script>";
		exit();
}
?>