Sitemap is a SEO Tool, exactly it's a links list include all pages links and properties for one website. It tell Search Engines how many pages in this website need be grabed, each page's priority and update frequency. Usually Search Engines will grab some pages and try find links page by page, the speed is very low and the accuracy is very low too(it's very hard to cover 80% pages).

So we need sitemap.xml to make this part easy, faster and accuracy.

{SiteMap.xml Standard Format}

<?xml version="1.0" encoding="utf-8"?>
<urlset xmlns="http://www.sitemaps.org/schemas/sitemap/0.9" 
	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 
	xsi:schemaLocation="http://www.sitemaps.org/schemas/sitemap/0.9 http://www.sitemaps.org/schemas/sitemap/0.9/sitemap.xsd">
	<url>
		<loc>http://yiilib.com/</loc>
		<lastmod>2016-05-03</lastmod>
		<changefreq>daily</changefreq>
		<priority>1.0</priority>
	</url>
	<url>
		...
	</url>
	...
</urlset>

{SiteMap.xml Standard Format Params}