What is CDN Fallback ?
CDN stands for Content Delivery Network.
The benefit of loading libraries like jQuery and Bootstrap from a CDN is that If Server is located multiple geographical location. It read or load the files from the nearest server, which ultimately speed up the page response time. example:-
There are 2 popular CDN exists in the market
1. Google
2. Microsoft
Google CDN:- https://developers.google.com/speed/libraries/
Microsoft CDN:- http://www.asp.net/ajax/cdn
In that scenario, It should read from your local server i.e.
</script>
Or (Another Way) :: Both are same
CDN stands for Content Delivery Network.
The benefit of loading libraries like jQuery and Bootstrap from a CDN is that If Server is located multiple geographical location. It read or load the files from the nearest server, which ultimately speed up the page response time. example:-
There are 2 popular CDN exists in the market
1. Google
2. Microsoft
Google CDN:- https://developers.google.com/speed/libraries/
<script src="//ajax.googleapis.com/ajax/libs/jquery/1.8.1/jquery.min.js"></script>
Microsoft CDN:- http://www.asp.net/ajax/cdn
<script src="http://ajax.aspnetcdn.com/ajax/jquery/jquery-1.9.0.js"></script>Fallback means :- If CDN server fails then WHAT ?
In that scenario, It should read from your local server i.e.
<script src=
"http://ajax.aspnetcdn.com/ajax/jquery/jquery-2.0.0.min.js"
></script>
<script>
if
(
typeof
jQuery ==
'undefined'
) {
document.write(unescape(
"%3Cscript src='/js/jquery-2.0.0.min.js' type='text/javascript'%3E%3C/script%3E"
));
}
Or (Another Way) :: Both are same
<script src=
"//ajax.aspnetcdn.com/ajax/jquery/jquery-2.0.0.min.js"
></script>
<script>window.jQuery || document.write(
'<script src="js/jquery-2.0.0.min.js">\x3C/script>'
)</script>