Need a quick refresh definition.

Jazzy_Girl

Hello, I could really use some help understanding something. Why does php have to refresh the whole page for a function to continue? For example.

<?php
$getfile = rand(1,5);
$includefile = "file" . $getfile . ".txt";
include ($includefile);
?>

Gets .txt randomly but in order for it to get a new random item the page needs reloaded or refreshed.

And in javascript the whole page doesn't need refreshed but just the function.
I know its because its a server side command but that doesn't tell me much. I need to understand "why" it must be the whole page, then I will know how to fix other problems. Thanks!

rincewind456

The php page is parsed through the web server (server side) and the resulting HTML output is sent to you (client side) for your browser to display, so if the page has to be refreshed then you have to go back to the server for a new page to be generated.

Javascript on the other hand works on your machine (client side) so if the javascipt enabled page has to be re-written then javascipt is capable of displaying new or altered content without having to go back to the server to do it.

Jazzy_Girl

Thank you very much! That makes it a bit clearer. I am going to try to break it down bit by bit until hopefully, evenutally, I understand it completely. So here goes.

PHP code on .php page>Read by server?
Returned to web page or directly to browser so browser can read it?
Function executed.

Why does it have to go back to server again through page reload to keep executing? Thanks.

rincewind456

Why does it have to go back to server again through page reload to keep executing?

It doesn't unless you need the content to change.

If, for example you have a page that acts as a calculator, in php the values you want to get the product of would have to be sent back to the server before the result could be displayed. In javascript the same function would be done entirely on the page you have already loaded, which can be altered by javascript without going back to the server.

Jazzy_Girl

Thanks a lot for explaining, I need my content to change, but also to be searched by search engines. Is there a way to go back to the server without the page refresh or load?

dougal85

google AJAX. but its really quite complicated. There are some libraries that make it easier.

It's an architecture where Javascript is used to call a phppage, that may contain many functions and then it updates just a portion of the page with this new php information. (not always php, but since your on this form i guess it will be 😉)

bradgrafelman

I was under the impression that AJAX isn't search-engine friendly, though, since bots like Googlebot won't be executing the JS code to retrieve the page content?

dougal85

That is true, but its only the case if you make your website a full AJAX application.

Something like gmail, windows live mail... they wont be search friendly.

However, if you don't AJAX the whole site and use it for particular features then it works well.

www.facebook.com does a really good job.

Weedpacket

Besides, an interactive application that would benefit from AJAX isn't generally the sort of thing it would make much sense having indexed by a search engine in the first place (application UIs, shopping carts, ....).

NogDog

I'd also like to point out that if you construct your HTML output to be well-structured, semantic mark-up using external CSS stylesheets for the visual presentation, then reloading your pages won't be a big deal (unless you're on a 2400-baud modem, perhaps).

Jazzy_Girl

Thanks for the leads anyway, looks like I have some work to do. I just did a bunch of searches, it looks like this might be tricky. I don't see a whole lot on keeping the php searchable using ajax.

dougal85

NogDog wrote:
I'd also like to point out that if you construct your HTML output to be well-structured, semantic mark-up using external CSS stylesheets for the visual presentation, then reloading your pages won't be a big deal (unless you're on a 2400-baud modem, perhaps).

good point and the new windows live mail thats meant to be so cool... is so friggin slow!!

Weedpacket

You can broaden your search by keeping in mind that search engines won't care what language you use on the server, whether it's PHP or something else; all that matters for this is what the end user sees.