[Dev]

I want to learn php or html what should i learn first ?
(of course for hacking purposes)

take html & javascript w/css & make something simple, All of these languages run together with php, PHP is the hardest & the most time consuming, Ruby on rails is a program built around the PHP construct, html, css, Jquery, Java & javascript all Co-ordinate with PHP. If you can figure out how to construct one web language, the Larger ones will be easier to retain.

I would suggest getting an e-book or something to explain the purpose of code, What I mean is that a book will go into detail about the exterior, It'll Explain it to you in a Hack friendly way, Like most hackers you are Curious, Probably a little obsessive, If you want to find an exploit, you need to read about each languages weaknesses & why they have them.

as for an HTML based site it'll tell you how to put the code together *10 year olds can do this*

PHP on the other-hand is practically pure hacking in one sense.. but without knowing each type of Codes element you'll Find it hard & frustrating to find exploits, Ultimately Starting low & going high will help you out & it should save you time & effort.