什么是JQuery的选择器呢，详见JQuery中的Selector: http://docs.jquery.com/Selectors

比如 $("div:contains('John')").css("text-decoration", "underline");的contains选择器等等

JQuery自定义选择器的基本语法：

$.expr[':'].test = function(obj, index, meta, stack){
    /* obj - is a current DOM element
       index - the current loop index in stack
       meta - meta data about your selector !!! 用来存参数值，详见带参数的自定义选择器。
       stack - stack of all elements to loop
   
       Return true to include current element
       Return false to explude current element
    */
};

// Usage:

$('.someClasses:test').doSomething();

1.创建一个简单的自定义选择器(将返回"rel"标签不为空的元素)

$.expr[':'].withRel = function(obj){

  var $this = $(obj);

  return ($this.attr('rel') != '');

};
// 应用:

$('a:withRel').css('background-color', 'yellow');

效果见：http://custom-drupal.com/jquery-demo/custom-selectors/

2. 创建带参数的自定义选择器，通过meta来实现.

语法:

$('a:test(argument)');

//meta would carry the following info: meta的格式如下（meta[3]对应的值是argument）

[

    ':test(argument)', // full selector

    'test',            // only selector

    '',                // quotes used

    'argument'         // parameters

]


$('a:test("arg1, arg2")');

//meta would carry the following info:

[

    ':test('arg1, arg2')', // full selector

    'test',                // only selector

    '"',                   // quotes used

    'arg1, arg2'           // parameters

]
 
实例：

$.expr[':'].withAttr = function(obj, index, meta, stack){

  return ($(obj).attr(meta[3]) != '');

};

应用：

$('a:withAttr(rel)').css('background-color', 'yellow');

 参考地址：

http://jquery-howto.blogspot.com/2009/06/jquery-custom-selectors-with-parameters.html

http://jquery-howto.blogspot.com/2009/06/custom-jquery-selectors.html

http://www.softwareunity.com/jquery/JQueryMoreSelectors/