(function ($) {
    // @todo Document this.
    $.extend($, { placeholder: {
        browser_supported: function () {
            return this._supported !== undefined ?
          this._supported :
          (this._supported = !!('placeholder' in $('<input type="text">')[0]));
        },
        shim: function (opts) {
            var config = {
                color: '#888',
                cls: 'placeholder',
                lr_padding: 4,
                selector: 'input[placeholder], textarea[placeholder]'
            };
            $.extend(config, opts);
            !this.browser_supported() && $(config.selector)._placeholder_shim(config);
        }
    }
    });

    $.extend($.fn, {
        _placeholder_shim: function (config) {
            function calcPositionCss(target) {
                var op = $(target).offsetParent().offset();
                var ot = $(target).offset();

                return {
                    top: ot.top - op.top + ($(target).outerHeight() - $(target).height()) / 2,
                    left: ot.left - op.left + config.lr_padding,
                    width: $(target).width() - config.lr_padding
                };
            }
            return this.each(function () {
                var $this = $(this);

                if ($this.data('placeholder')) {
                    var $ol = $this.data('placeholder');
                    $ol.css(calcPositionCss($this));
                    return true;
                }

                var possible_line_height = {};
                if (!$this.is('textarea') && $this.css('height') != 'auto') {
                    possible_line_height = { lineHeight: $this.css('height'), whiteSpace: 'nowrap' };
                }

                var ol = $('<label />')
          .text($this.attr('placeholder'))
          .addClass(config.cls)
          .css($.extend({
              position: 'absolute',
              display: 'inline',
              float: 'none',
              overflow: 'hidden',
              textAlign: 'left',
              color: config.color,
              cursor: 'text',
              paddingTop: $this.css('padding-top'),
              paddingLeft: $this.css('padding-left'),
              fontSize: $this.css('font-size'),
              fontFamily: $this.css('font-family'),
              fontStyle: $this.css('font-style'),
              fontWeight: $this.css('font-weight'),
              textTransform: $this.css('text-transform'),
              zIndex: 99
          }, possible_line_height))
          .css(calcPositionCss(this))
          .attr('for', this.id)
          .data('target', $this)
          .click(function () {
              $this.data('target').focus()
          })
          .insertBefore(this);
                $this
          .data('placeholder', ol)
          .focus(function () {
              ol.hide();
          }).blur(function () {
              ol[$this.val().length ? 'hide' : 'show']();
          }).triggerHandler('blur');
                $(window)
          .resize(function () {
              var $target = ol.data('target')
              ol.css(calcPositionCss($target))
          });
            });
        }
    });
})(jQuery);

jQuery(document).add(window).bind('ready load', function () {
    if (jQuery.placeholder) {
        jQuery.placeholder.shim();
    }
});