/*

 * In-Field Label jQuery Plugin

 * http://fuelyourcoding.com/scripts/infield.html

 *

 * Copyright (c) 2009 Doug Neiner

 * Dual licensed under the MIT and GPL licenses.

 * Uses the same license as jQuery, see:

 * http://docs.jquery.com/License

 *

 * @version 0.1

 */

(function($){

    $.InFieldLabels = function(label,field, options){

        // To avoid scope issues, use 'base' instead of 'this'

        // to reference this class from internal events and functions.

        var base = this;

        // Access to jQuery and DOM versions of each element

        base.$label = $(label);

        base.label = label;



 		base.$field = $(field);

		base.field = field;

        

		base.$label.data("InFieldLabels", base);

		base.showing = true;

        

        base.init = function(){

        	

			// Merge supplied options with default options

            base.options = $.extend({},$.InFieldLabels.defaultOptions, options);



			// Check if the field is already filled in

			if(base.$field.val() != ""){

				base.$label.hide();

				base.showing = false;

			};

			

			base.$field.focus(function(){

				base.fadeOnFocus();

			}).blur(function(){

				base.checkForEmpty(true);

			}).bind('keydown.infieldlabel',function(e){

				// Use of a namespace (.infieldlabel) allows us to

				// unbind just this method later

				base.hideOnChange(e);

			}).change(function(e){

				base.checkForEmpty();

			}).bind('onPropertyChange', function(){

				base.checkForEmpty();

			});

        };



		// If the label is currently showing

		// then fade it down to the amount

		// specified in the settings

		base.fadeOnFocus = function(){

			if(base.showing){

				base.setOpacity(base.options.fadeOpacity);

			};

		};

		

		base.setOpacity = function(opacity){

			base.$label.stop().animate({ opacity: opacity }, base.options.fadeDuration);

			base.showing = (opacity > 0.0);

		};

		

		// Checks for empty as a fail safe

		// set blur to true when passing from

		// the blur event

		base.checkForEmpty = function(blur){

			if(base.$field.val() == ""){

				base.prepForShow();

				base.setOpacity( blur ? 1.0 : base.options.fadeOpacity );

			} else {

				base.setOpacity(0.0);

			};

		};

		

		base.prepForShow = function(e){

			if(!base.showing) {

				// Prepare for a animate in...

				base.$label.css({opacity: 0.0}).show();

				

				// Reattach the keydown event

				base.$field.bind('keydown.infieldlabel',function(e){

					base.hideOnChange(e);

				});

			};

		};



		base.hideOnChange = function(e){

			if(

				(e.keyCode == 16) || // Skip Shift

				(e.keyCode == 9) // Skip Tab

			  ) return; 

			

			if(base.showing){

				base.$label.hide();

				base.showing = false;

			};

			

			// Remove keydown event to save on CPU processing

			base.$field.unbind('keydown.infieldlabel');

		};

      

		// Run the initialization method

        base.init();

    };

	

    $.InFieldLabels.defaultOptions = {

        fadeOpacity: 0.5, // Once a field has focus, how transparent should the label be

		fadeDuration: 300 // How long should it take to animate from 1.0 opacity to the fadeOpacity

    };

	

    

    $.fn.inFieldLabels = function(options){

        return this.each(function(){

			// Find input or textarea based on for= attribute

			// The for attribute on the label must contain the ID

			// of the input or textarea element

			var for_attr = $(this).attr('for');

			if( !for_attr ) return; // Nothing to attach, since the for field wasn't used

			

			

			// Find the referenced input or textarea element

			var $field = $(

				"input#" + for_attr + "[type='text']," + 

				"input#" + for_attr + "[type='password']," + 

				"textarea#" + for_attr

				);

				

			if( $field.length == 0) return; // Again, nothing to attach

			

			// Only create object for input[text], input[password], or textarea

            (new $.InFieldLabels(this, $field[0], options));

        });

    };

	

})(jQuery);