jQuery Custom Selector JQuery自定义选择器

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');