anti-hackers coding(anti XSS coding behaviors)?

i am into php coding for 1 year now. i don't know everything or consider myself professional.but i want to write clean hacker proof coding. i tried to research for example how to stop XSS attacks.but it seems that there is a l开发者_运维知识库ot of expressions and a lot of vulnerabilities. i tried htmlawed and html purifiers. but not every simple form or script i write will need heavy script to make it secure. so what i need is : is there a coding style that i can follow that make my coding secure?

Basically, to avoid XSS, you have to make sure no HTML can be injected by the users into the HTML output of your page.

The simplest way of doing that is to use functions such as htmlspecialchars() on any output that goes to the browser as HTML.

This means that, if anyone inputs something like this (simple example) :

<script>alert('plop');</script>

The HTML of your page will contain :

<script>alert('plop');</script>

And no HTML / Javascript code that could be interpreted.