jquery.custom_extensions.js

(function($) {
  $.fn.disable = function(){
    return this.attr('disabled', 'disabled');
  };
  $.fn.enable = function(){
    return this.removeAttr('disabled');
  };
  
  $.fn.findOrAppend = function(selector, html){
    var results = this.find(selector);
    if (results.length > 0){
      return results;
    } else {
      html = $(html);
      this.append(html);
      return html;
    }
  };
  
  $.fn.margin = function(side){
     return this[0] && parseInt( jQuery.curCSS(this[0], ('margin'+side), true), 10 ) || 0;
  };

  $.overlap = function(e1, e2){
    var el1 = $(e1), el2 = $(e2);

    var e1x1 = (el1.position().left-el1.margin('Left')), e1x2 = (el1.position().left+el1.outerHeight()+el1.margin('Right')),
        e1y1 = (el1.position().top-el1.margin('Top')), e1y2 = (el1.position().top+el1.outerHeight()+el1.margin('Bottom'));

    var e2top = (el2.position().top-el2.margin('Top')), e2left = (el2.position().left-el2.margin('Left')),
        e2width = el2.outerWidth(true), e2height = el2.outerHeight(true);

    return ($.ui.isOver(e1y1, e1x1, e2top, e2left, e2height, e2width) ||
            $.ui.isOver(e1y1, e1x2, e2top, e2left, e2height, e2width) ||
            $.ui.isOver(e1y2, e1x1, e2top, e2left, e2height, e2width) ||
            $.ui.isOver(e1y2, e1x2, e2top, e2left, e2height, e2width));
  };
})(jQuery);