what is the # symbol in the url

Question

I went to some photo sharing site, so when I click the photo, it direct me to a url like

www.example.com/photoshare.php?photoid=1234445

. and w

Answer 1

It's called the fragment identifier. It identifies a "part" of the page. If there is an element with a name or id attribute equal to the fragment text, it will cause the page to scroll to that element. They're also used by rich JavaScript apps to refer to different parts of the app even though all the functionality is located on a single HTML page.

Lately, you'll often see fragments that start with "#!". Although these are still technically just fragments that start with the ! character, that format was specified by Google to help make these AJAXy pseudo-pages crawlable.