This JavaScript/jQuery code is a mix of basic form handling...

This JavaScript/jQuery code is a mix of basic form handling and obfuscation, making it harder to understand at first glance. Let's break it down step by step.

What does the code do?

1. Detects when the DOM is fully loaded:

   $(document).ready(function() {
   

   This ensures that the code inside the block will only run after the HTML document has been fully loaded, preventing potential issues with trying to manipulate elements that may not yet exist.

2. Handles a click on an element with the ID submit:

   $("#submit").click(function(e) {
       e.preventDefault();
   

   The click event is attached to the element with the id="submit". When this button is clicked, the default action of the event (such as submitting the form) is prevented using e.preventDefault().

3. Reads the username and password entered by the user:

   var user = $("#username").val();
   var pass = $("#password").val();
   

   • The code retrieves the value of the input field with the id="username" and stores it in the variable user.
   • Similarly, it retrieves the value of the input field with the id="password" and stores it in the variable pass.

4. Checks if the username and password match a predefined value:

   words = ["vary", "ends", "broccoli", "alike"];
   if ((user === "admin") && (pass === words[1] + "-" + words[0] + "-" + words[3] + "-" + words[2])) {
   

   • A static array words is created with the values "vary", "ends", "broccoli", and "alike".
   • The if condition checks:
     • If user is equal to "admin".
     • If pass is equal to a concatenated string that uses elements from the words array in this order: ends-vary-alike-broccoli.

5. Modifies the content of an element with the ID output:

   If the user enters the correct username and password, the following code is executed:

   $("#output").empty().append((function(){...})());
   

   • $("#output") selects the element with the id="output".
   • .empty() clears any content that was previously in the element.
   • .append(...) adds the decoded content (explained below) to the element.

6. Generates and appends an obfuscated string:

   The obfuscation used involves several anonymous functions that manipulate arrays of numbers to produce a final string. Decoding these functions reveals the final string.

   Here is what happens in each section:

   • First Anonymous Function:

     (function(){var P=Array.prototype.slice.call(arguments),S=P.shift();return P.reverse().map(function(B,c){return String.fromCharCode(B-S-29-c)}).join('')})(6,155,145,116,150,140,72,97,141,134,144,105)
     

     This computes the first portion of the string by reversing an array of hardcoded numbers, modifying their values, and converting them into characters.

   • Second Portion:

     (10).toString(36).toLowerCase().split('').map(function(f){return String.fromCharCode(f.charCodeAt()+(-13))}).join('')
     

     This converts the number 10 into base-36 ("a"), shifts each character, and builds part of the string.

   • Similar logic is repeated multiple times to compute different segments of the string.

Output Behavior

The obfuscated code eventually produces a hardcoded string using numerical transformations. The content of #output is updated to this string if the user enters the correct username ("admin") and password ("ends-vary-alike-broccoli").

TL;DR

• The code waits for the user to click on a "submit" button.
• It compares the entered username and password to predefined values (with the password being constructed dynamically from the words array).
• If the credentials match, it outputs an obfuscated string into an HTML element with the ID output.
• The obfuscation steps are intentionally convoluted, possibly to prevent casual inspection of the output string or logic.