Yes, sound weird. But I'm trying to make a text editor inside the browser. I've seen some programs use it. Like wordpress and unet. But I'm not sure if they use a custom one or not. However, this topic explains why geshi won't work in textarea: Why isn't textarea an input[type="textarea"]? I simply get the code of the colors. Just wondering if there's a way around this. I've tried searching but I was without luck.
<textarea><?php geshi_highlight($source, 'php'); ?></textarea>
edit::the variable $source contains php code.
Output is basically the span style that geshi outputs.