A search engine crawls your website through reading the codes created with code languages including PHP, HTML, ASP, and more. Search engine to simply identify links and use that as a driver for Search Engine Optimization toward your website. Read these document by YourSEOPick to understand Search Engines read your website.

2. How and What are Search Engines Reading On Your website?
Every search engine doesn’t see web pages like the way you do. It can’t
process images and translate these into content. A search engine crawls
your website through reading the codes created with code languages
including PHP, HTML, ASP, and more. A web page that’s made up mostly of
images shows mostly blank to search engines.
There are times that what you see as text on the page is not really text.
Several people make web page designs in a particular image editor program
and rather than recreating the design as codes, they post their image to look
like HTML.
An image of text is not an actual text, it is only a picture and it is not visible
to search engines. All search engines may see it as a blank spot where the
image is located. This is also the same with video and audio. Several
interactive pages that are created in Flash may be invisible to the search
engines.
Having pages on website with tons of images and flash animations is fine,
yet it depends on your target customers. Image gallery websites want to
showcase their images. Nevertheless, it isn’t search­engine friendly.
Therefore, if the business model you have depends on being found by search
engines, you must think about including several pages with a descriptive
text. This makes it easier for search engines to rank and find your website.
Adding some text descriptions to the images can also help your website.
Search Engines – How Do They Operate?

3. How and What are Search Engines Reading On Your website?
Understanding how search engines function will surely take the mystery out
of why SEO is important any online business that wants to achieve success.
The search engines such as MSN, Yahoo, and Google perform these tasks:
 A search engine uses programs called spiders or bots to crawl the
internet when looking for pages.
 Once the spider or bot finds and craws a web page, it stores in the
database of the search engine. The process is known as indexing. The
index of a search engine contains all pages and documents the bots or
spiders have crawled.
 A search engine processes queries. For example, once you go to
Google as well as type in the keyword “cheap camping gear” into the
search box, this search engine will process your query and return you
the results based on what you’re searching for. Millions of such
queries take place daily.
 The search engine’s final function is ranking results. Once you type in
the query above, search engines run quickly a sorting equation to see
which results it feels are relevant to your query. Algorithm is the
sorting equation and every search engine has various algorithms. In
other terms, they have several priorities about what pages they think
are the perfect match for the query. They perform this big task of
choosing the best results in seconds and SEO revolves around making

4. How and What are Search Engines Reading On Your website?
pages that search engines find to be the most relevant and best
matches for essential queries.
All in all, a search engine works through indexing, crawling, processing the
queries, and ranking the results.