$(function() {
		// a workaround for a flaw in the demo system (http://dev.jqueryui.com/ticket/4375), ignore!
		$( "#dialog:ui-dialog" ).dialog( "destroy" );

		var username = $( "#username" ),
			password = $( "#password" ),
			allFields = $( [] ).add( username ).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: 270,
			width: 350,
			modal: true,
            resizable: false,
			buttons: {
				"Login": function() {
					var bValid = true;
					allFields.removeClass( "ui-state-error" );

					bValid = bValid && checkLength( username, "username", 3, 10 );
					bValid = bValid && checkLength( password, "password", 5, 15 );

					bValid = bValid && checkRegexp( username, /^[a-z]([0-9a-z_])+$/i, "Username may consist of a-z, 0-9, underscores, begin with a letter." );
					bValid = bValid && checkRegexp( password, /^([0-9a-zA-Z])+$/, "Password field only allow : a-z 0-9" );

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

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