Fast CSS Style Switching with PHP

Of course, this can be done easily in other languages too. In old-style JSP (which, like PHP, puts Java code straight into the page), it would look like this:


<%
String cssFile = request.getParameter("css");
if (cssFile == null || "".equals(cssFile)) {
cssFile = /css/thestylefile.css;
}
%>
<style type="text/css"><!--
@import url(<%= cssFile %>)
-->;</style>


By the way, in your PHP example, wouldn't it be better practice to return the filename rather than echo it out directly?

Sorry I couldn't get the code to line up - the pre tag wasn't allowed. Maybe you could add a white-space:pre to your CSS for the code tag?

Well, I think returning a value from the function instead of using echo would make the function more flexible and reusable. For example, you might have another function that might want to call your css() function and manipulate the filename somehow, or use the filename in a call to yet another function.

You may not need that sort of functionality right now, but it makes it easy to reuse it in different ways in the future.

Why not set a cookie with selected stylesheet to make user's choice more or less permanent?

Change if(isset($_GET['css'])) .. to if(isset($_GET['css']) || isset($_COOKIE['css'])) { $style = $_REQUEST['css']; setcookie('css', $style); }

By the way: Would be nice to check via file_exists() if the desired stylesheet defined in your GET-params is really there :-)

Though PHP is indeed very handy for things like this, always validate your input... last thing we want is a compromised and defaced server as some smart arse started injecting HTML/PHP/SQL via "GET".

Just a simple change:

echo $style;
}


We're not really bothered if the variable is set, we're more concerned if the one that is set hasn't got escaped nasties like single or double quotes and also if the file actually exists on the filesystem, where 'a/path/prefix' is whatever actual path is needed to get to '/css/thestylefile.css', say '/home/user/htdocs'.

A PHP based styleswitcher has been a permanent feature of my site for a while... decided to use cookies over PHP sessions though. :D

Been there, done that, bought shirt. :P Very unobtrusive too.

What's far more effektive for webdevelopers, is semi-automatic-generating of CSS via PHP:

$css["color"] ="black";

$css["background-site"]="#D6CFC4";

$file_css = fopen ("test.css", "w+");

fwrite ($file_css, "html {font-size:x-small; font-weight:normal;

background-color:".$css["background-site"]."; color:".$css["maincolor"]."; }n");

fclose($file_css) ;

So you can define central-formats like colors, fonts, sizes in an array and add them dynamically in the css.

You could even do something like this:

$css["mode"][0]["color"] ="#F7941D";//CMYK 0/50/100/0

$css["mode"][0]["backgroundcolor"] ="#FCE4C7";

$css["mode"][0]["subbordercolor"] ="#FFD182";

$css["mode"][1]["color"] ="#F37021";//CMYK 0/70/100/0

$css["mode"][1]["backgroundcolor"] ="#F8DECE";

$css["mode"][1]["subbordercolor"] ="#F5A270";

$file_css = fopen ("test.css", "w+");

$counter=0;

while($conf["mode"][$counter]["color"]!=""){

fwrite ($file_css, "em.mode".$counter." n");

fwrite ($file_css, "#content-mode".$counter." em n");

$counter++;

}

fclose($file_css) ;

[I'm sorry for the empty "p"-elements in my comment, but the pre-element is not allowed here. How else should I markup an empty line ?]

Mike, I have to agree that returning values from functions is better than echoing within functions. Why?
Lots of stylistic reasons, but in addition, let's assume that you are writing spaghetti code. You definitely want to assign the return value of the function to a variable and then plug the var into a template later on. If not, what if you decide later on your page that you need to send some http headers? Death.