| /** | |
| * A function to swap keys with values | |
| * in a JavaScript object. | |
| * | |
| * {a: 'b', c: 'd'} => {b: 'a', d: 'c'} | |
| */ | |
| function reverseObject(obj) { | |
| const reducer = (accumulator, [key, value]) => Object.assign(accumulator, {[value]: key}) | |
| return Object.entries(obj).reduce(reducer, {}) |
| /challenges/learn-how-freecodecamp-works | |
| /challenges/challenges/basic-html-and-html5/learn-how-freecodecamp-works | |
| /challenges/join-a-freecodecamp-study-group-in-your-city | |
| /challenges/basic-html-and-html5/join-a-freecodecamp-study-group-in-your-city | |
| /challenges/iterate-odd-numbers-with-a-for-loop | |
| /challenges/basic-javascript/iterate-odd-numbers-with-a-for-loop | |
| /challenges/count-backwards-with-a-for-loop |
XSS stands for Cross-site scripting, and it's a security vulnerability. It's when an attacker can inject certain code into a vulnerable website, which could decieve or take over an account of a victim.
Let's say I have an input field on my website, where anybody can leave a comment. This comment will, for simplicity, replace the previous comment.
<div>
Hah! This is such a cool site!
Ok, so, you might know about JavaScript regular expressions. Well, here is a tutorial about them, but written by a 13 year old, so it isn't actually any good!
Regular expressions go between / characters. Here is an exampe, /hi/.
Ok, now then. Let's learn how to match the string abc. Well, that's quite simple.
/abc/. Yey! So putting letters next to each other makes them match one after the other.
Ok, now, after the second / we can put a g to make it match globally, that is, we can extract abc from xyzabcghi.
| // Solution below | |
| £(log(2*2^2+2)*7/2+18/4)/(2^(4^3-(3^3+5*7-1)))-1 |
| """ This is a grammar file for the ATC #3 challenge by @MegaApuTurkUltra """ | |
| if => "IF" condition result result | |
| condition => result "EQUALS" result | |
| | result "LESSTHAN" result | |
| | result "GREATERTHAN" result | |
| protect => "PROTECT" reference |