Well, its a the cheatsheets by Davey Shafik (http://pixelated-dreams.com).
Yes, you make the treatment in every string become user.
Why I make it?It’s sample, your script give more security after this. Try!

If you prefer pdf version click here. (FilteringAndEscapingCheatSheet.pdf)

Yes, every languages start with Hello World, there is not be differente here.

<?=”Hello World”; ?>, this blog starts now.