我正在学习jQuery,在阅读本书时,有一个代码,你在那里制作自定义选择器。这是代码
(function($) {
$.extend($.expr[':'], {
group: function(element, index, matches, set) {
var num = parseInt(matches[3], 10);
if (isNaN(num)) {
return false;
}
return index % (num * 2) < num;
}
});
})(jQuery);
这里正在调用
$(document).ready(function() {
function stripe() {
$('#news').find('tr.alt').removeClass('alt');
$('#news tbody').each(function() {
$(this).children(':visible').has('td')
.filter(':group(3)').addClass('alt');
});
}
stripe();
});
我知道.filter()为每个子元素运行。假设如果我的tbody元素有4个tr(行),则.filter为每个tr运行(隐式迭代)。 现在当调用.filter(':group(3)')时,我注意到传递给:group function的参数是。
第一次成为
group:function(element,index,matches,set)
元素为tr , index为0 , mathces成为[“:group(3)”,“group”,“”,“3”] 和设置为[tr,tr,tr,tr,tr]
现在我解读了set,每个tbody标签都有tr的数量,成为set array。但是请告诉我parseInt(匹配[3],10)是如何工作的?
我想问一下jQuery是如何制作匹配数组的。我只想写:组(3)。如何将值设置为参数列表中的这些值?
以下是html的片段
<table id="news">
<thead>
<tr>
<th>Date</th>
<th>Headline</th>
<th>Author</th>
<th>Topic</th>
</tr>
</thead>
<tbody>
<tr>
<th colspan="4">2011</th>
</tr>
<tr>
<td>Apr 15</td>
<td>jQuery 1.6 Beta 1 Released</td>
<td>John Resig</td>
<td>Releases</td>
</tr>
<tr>
<td>Feb 24</td>
<td>jQuery Conference 2011: San Francisco Bay Area</td>
<td>Ralph Whitbeck</td>
<td>Conferences</td>
</tr>
<tr>
<td>Feb 7</td>
<td>New Releases, Videos & a Sneak Peek at the jQuery UI Grid</td>
<td>Addy Osmani</td>
<td>Plugins</td>
</tr>
<tr>
<td>Jan 31</td>
<td id="release">jQuery 1.5 Released</td>
<td>John Resig</td>
<td>Releases</td>
</tr>
<tr>
<td>Jan 30</td>
<td>API Documentation Changes</td>
<td>Karl Swedberg</td>
<td>Documentation</td>
</tr>
</tbody>
<tbody>
<tr>
<th colspan="4">2010</th>
</tr>
<tr>
<td>Nov 23</td>
<td>Team Spotlight: The jQuery Bug Triage Team</td>
<td>Paul Irish</td>
<td>Community</td>
</tr>
<tr>
<td>Oct 4</td>
<td>New Official jQuery Plugins Provide Templating, Data Linking and Globalization</td>
<td>John Resig</td>
<td>Plugins</td>
</tr>
<tr>
<td>Sep 4</td>
<td>The Official jQuery Podcast Has a New Home</td>
<td>Ralph Whitbeck</td>
<td>Documentation</td>
</tr>
<tr>
<td>Aug 24</td>
<td>jQuery Conference 2010: Boston</td>
<td>Ralph Whitbeck</td>
<td>Conferences</td>
</tr>
<tr>
<td>Aug 13</td>
<td>The jQuery Project is Proud to Announce the jQuery Mobile Project</td>
<td>Ralph Whitbeck</td>
<td>Plugins</td>
</tr>
<tr>
<td>Jun 14</td>
<td>Seattle jQuery Open Space and Hack Attack with John Resig</td>
<td>Rey Bango</td>
<td>Conferences</td>
</tr>
<tr>
<td>Mar 16</td>
<td>Microsoft to Expand its Collaboration with the jQuery Community</td>
<td>John Resig</td>
<td>Miscellaneous</td>
</tr>
<tr>
<td>Mar 15</td>
<td>jQuery Conference 2010: San Francisco Bay Area</td>
<td>Mike Hostetler</td>
<td>Conferences</td>
</tr>
<tr>
<td>Jan 14</td>
<td>jQuery 1.4 Released</td>
<td>John Resig</td>
<td>Releases</td>
</tr>
<tr>
<td>Jan 8</td>
<td>14 Days of jQuery and the New API Browser</td>
<td>John Resig</td>
<td>Documentation</td>
</tr>
</tbody>
<tbody>
<tr>
<th colspan="4">2005</th>
</tr>
<tr>
<td>Dec 17</td>
<td>JSON and RSS</td>
<td>John Resig</td>
<td>Documentation</td>
</tr>
<tr>
<td>Dec 14</td>
<td>Google Homepage API</td>
<td>John Resig</td>
<td>Miscellaneous</td>
</tr>
<tr>
<td>Dec 13</td>
<td>XPath and CSS Selectors</td>
<td>John Resig</td>
<td>Miscellaneous</td>
</tr>
<tr>
<td>Dec 12</td>
<td>Sparklines with JavaScript and Canvas</td>
<td>John Resig</td>
<td>Miscellaneous</td>
</tr>
</tbody>
</table>
由于
答案 0 :(得分:1)
在您的示例中,matches[3] == "3"
。因此parseInt(matches[3], 10);
会将“3”转换为整数3(基数10 =十进制)。