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Federico Piragua
Federico Piragua

Reputation: 707

How do I pre-cache a page before it redirects to it?

As seen in YouTube, when you click a YT link it before redirecting you it preloads the layout of the page and then it redirect yoo it, for you to not having to see how the layout items load.

How do I make this with, JavaScript, PHP, HTTP, jQuery or with any other language?

Upvotes: 0

Views: 159

Answers (1)

Charles
Charles

Reputation: 4362

I don't think you really understand what is going on behind the scenes at YouTube. You see, the template/layout doesn't always change. The data always changes. It isn't loading the layout (unless the new page has a different template, such as sending a message or viewing a user profile), it is fetching the data from a database and then it uses javascript to replace the current data on the page with the data it just fetched. It does this through AJAX. They use Python on the back end.

Basically... this is what happens when you click a link for a new video:

1) You click the link.

2) Some JavaScript code makes an XMLHttpRequest to a script on the server which processes the request. A progress bar appears on the screen.

3) The script on the server connects to a database and grabs the information... like other videos in the playlist, comments, the video description, etc. It does this by submitting a query to the database.

4) The query returns the information to the script which in turn organizes it and returns it to the AJAX request (asynchronously, of course).

5) The JavaScript receives the information that it was waiting for and updates the HTML of the page. The JavaScript also does some other stuff behind the scenes, like update the URL and browsing history so that you can hit your "back" button and return to the previous page that you were on. (If the template for the newly requested page is different, the JavaScript will restructure the HTML of the page appropriately.)

Upvotes: 2

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