ID:1845843
 
(See the best response by Lummox JR.)
Code:
<style>

#Titlescreen{
background-image: url("Background.png");
width: 640px;
height: 480px;
top: 0;
left: 0;

}

</style>


<body>
<div id = "Titlescreen" byondclass = "label"></div>
</body>


Problem description:

So, I decided to mess with the webclient. Problem is, NOTHING appears on my screen. I literally have to put it in winset() for these functions to work. All I get is a white screen. Can someone please tell me what the issue with this code is?

I suggest opening developer tools in your browser and inspecting the frame. Is the div present, and if so is it the size you expect? The label has no content by default, remember, unless you send it output or use winset. And this skin is only a label, so it has no map, input, output, etc. If you want to use a default skin but put this label over it, I would either copy defaultSkin.dms or else create the label at runtime. (I really should add an option that gives you the output from a translated .dmf skin, too; then you could simply modify that.)

I also recommend losing the spaces around the = in your HTML; that's not good form, although it's unlikely to affect anything.
All the inspecter reveals is whatever you put in the winset() command. For example:
client
New()
winset(src, "Titlescreen", "background-color = #000")
..()


This is how I'm displaying my code in the first post. All that happens is the background color (that is also off the screen and you can barely see it. It's just a black bar on the top) None of the CSS is shown in the inspector
You might need to refresh the inspector's info to see it, but you should be able to see the label div there somewhere--especially if the background color change does show up. It seems that the label may not be respecting your size being set in CSS for some reason. You could try changing that so instead of CSS you give it a skinparams attribute:

skinparams="pos=0,0;size=640x480"

I admit I'm curious why the size isn't being used as-is, though. The label ought to use whatever it's told unless the size is set explicitly via the initial skinparams or winset.
Ok, I added the paramaters as you said. The image won't show up though. From what I'm see, nothing in CSS is effecting the label.
The image not showing up may be a separate problem. I'd first like to narrow down if the div is even there, and what size it is.
The div for the CSS doesn't show up at all. Here's a screenshot I took:

I'm not sure what you're looking for, but if you're trying to find the code within your <style> tags look within the <head> tags within your inspector. You might want to also make sure your style tags and such are defined within a head tag in your own html code as well, i'm not really familiar with the webclient to any extent, but just going off html practices.
I ended up finding where the CSS was. It's in the <header> tags.

Best response
Try changing your identifier to all lowercase, including in the CSS.
Oh wow, it actually worked! I guess all I had to do was make the id lowercase. Thank you Lummox Jr!
Guess you're gonna ignore the 'check in the <head> tags for your css' comment i posted.. alright, lol.

#noRecognitionForMe? ;_;
I didn't O.o I showed you what I got. Thank you as well Turboskill.
I noticed the ID got sanitized when the control loaded, so that was why I suggested lowercase.
Heheh, why thanks you! :3 (i'm just kidding around lol)