Just a quick note as I use this function in various scripts. This adds the 1000th separator comma:

    	FormatAddCommas(val) {
    		Result:=val
    		StringLen, OutputVar, Result
    		NumLoop := (OutputVar // 3)
    		DNum = 3
    		Loop, % (NumLoop+1)
    		{
    		   StringRight,Digit,Result,%DNum%
    		   StringReplace, Result, Result, %Digit%,`,%Digit%
    		   DNum += 4
    		}
    		StringLen, OutputVar, Result
    		Loop, %OutputVar%
    		{
    			FirstChar:=Substr(Result, 1, 1)
    			IfEqual, FirstChar, `,
    			{
    				Result:=Substr(Result, 2)
    			} else {
    				break
    			}
    		}
    		Return Result
    	}

Ok so there are more fun things to do out there. If you're the type of AutoHotkey programmer that doesn't like having to use the command prompt to write to an extra text file which your program has to read, then this is for you. DllCall will usually run contained in the program and can be hidden from the end-user.

The one to rule them all:
This is a function I pulled from the Autohotkey forums submitted by SKAN which lists all the functions for a specified Dynamic Link Library (DLL) along with an inputbox for convenience:

What's this all about? Well I want the basic hover effect: when my mouse cursor hovers over a link, I want that link to turn blue and display an underline. When I move the cursor away from the link, I want the link returned to black without an underline.

How?

Well yes you could just use the Unicode version of Autohotkey. If you're looking for some up and down arrows which is all I wanted, then you don't have to use Unicode and you can use the Chr() function:

msgbox % Chr(24) ; upwards arrow
msgbox % Chr(25) ; downwards arrow, unstable

As you can tell these are my messed up functions that convert dates into seconds and vice-versa. They're a little disorganised but they're the ones I copy and paste to my scripts then modify.

In it's straightforward form

FormatTime( TimeString, Format )
{
     FormatTime, FormattedTime , TimeString, %Format% 
     return Formattedtime
}

These are for autohotkey and in AHK code. Taken from Autohotkey forums topic 1878:

• From Hexadecimal to RGB
• From RGB to Hexadecimal
• Check for a valid hexadecimal value

Apologies for copying this from another source but with lots of OpenSource developers disappearing and reappearing, the content is what I don't want to lose.

 Couldn't find this anywhere on the net and kinda needed it so am making a note of how to do it here.

The issue is that I wanted to make my autohotkey program change the image that the mouse hovers over (within it's own GUI).  No third-party component or dll needed, just a slight modification to the mousemove tooltip in the autohotkey manual.