What should everyone know about web development?

To interact with this page you must login. Signup

technology

advice

tynamite

How to make a web design, slice it, and then make it responsive.
A server side language such as ruby, php, python, perl, asp.
Javascript is a dark art. To get results with it, you have to go hunting and stitch stuff together from other places.
That Microsoft, Apple, Opera, Adobe, Google and Mozilla all have their dedicated resources for learning HTML5 and adapting stuff for smartphones and tablets.
That it's always better to make your designs for Opera (then Firefox) first, then other browsers after.
The latest developments of HTML5 that happen as they get made.
There are loads of server side frameworks, css frameworks, canvas, svg, and animation frameworks, so you have to investigating to find out the best one for you.
What Firebug or the Web Inspector is.
How to protect yourself from being hacked and implement good security. Also backup your websites often.
That it's always good to overestimate when you have clients, because if some funky error comes up and something doesn't work, you'll have to wait whilst you get help or work on it for much longer, before it gets fixed.
That every website runs on a different "stack" and each web developer has their own tools. Different people code in different ways, and most people hate other people's code because it's messy or weird.