Box Shadow Spread Bug in Webkit in iOS 7 on Retina Ipads

Box-shadow not shown on Safari Mobile on iOS 7 (in landscape)

Adding border-radius: 1px fixed the problem:

h1 {
    box-shadow: 0 4px 9px -8px #000000;
    border-radius: 1px;
    color: #D95B43;
    height: 1.2em;
    margin-top: 0;
    font-size: 1.3em;
    padding: 10px;
}

From: https://stackoverflow.com/a/21323644/1565597 .

iPhone iOS will not display box-shadow properly

Try adding -webkit-appearance: none; iOS tends to mess up forms.

Safari 6: On an IMG, when box-shadow spread set to 0 AND a background-color value is set, no box-shadow is rendered at all

It seems like a bug indeed. However, if you use rgba notation for the background-color, the shadow reappears.

img{
 background-color: rgba(255,255,0,0);
 box-shadow: #000 2px 2px 10px 0px;
 -webkit-transform: translate3d(2px, 5px, 0px); 
}

http://jsfiddle.net/willemvb/KuhQp/

Difference between processes running in kernel mode and running as root?

kernel mode and root are two separate ideas that aren't really related to each other. The concept of running a process as root is a unix/linux term that means you're logged in as the administrator of the system.

Any process you run, whether as root or a normal user, generally runs in both user mode and kernel mode. The system is continually switching between user mode (where the application code runs) and kernel mode (where the kernel code runs).

Some programs, like many device drivers, always run in kernel mode, meaning they have full access to the hardware. A normal application running with root privileges still exists in user mode and only switches to kernel mode when a kernel system call is made and then switches right back to user mode.

Is it valid to replace http:// with // in a script src=http://...?

A relative URL without a scheme (http: or https:) is valid, per RFC 3986: "Uniform Resource Identifier (URI): Generic Syntax", Section 4.2. If a client chokes on it, then it's the client's fault because they're not complying with the URI syntax specified in the RFC.

Your example is valid and should work. I've used that relative URL method myself on heavily trafficked sites and have had zero complaints. Also, we test our sites in Firefox, Safari, IE6, IE7 and Opera. These browsers all understand that URL format.