Jsfinder - Fetches JavaScript Files Quickly And Comprehensively

jsFinder is a command-line tool written in Go that scans web pages to find JavaScript files linked in the HTML source code. It searches for any attribute that can contain a JavaScript file (e.g., src, href, data-main, etc.) and extracts the URLs of the files to a text file. The tool is designed to be simple to use, and it supports reading URLs from a file or from standard input.

jsFinder is useful for web developers and security professionals who want to find and analyze the JavaScript files used by a web application. By analyzing the JavaScript files, it's possible to understand the functionality of the application and detect any security vulnerabilities or sensitive information leakage.

Features

Reading URLs from a file or from stdin using command line arguments.
Running multiple HTTP GET requests concurrently to each URL.
Limiting the concurrency of HTTP GET requests using a flag.
Using a regular expression to search for JavaScript files in the response body of the HTTP GET requests.
Writing the found JavaScript files to a file specified in the command line arguments or to a default file named "output.txt".
Printing informative messages to the console indicating the status of the program's execution and the output file's location.
Allowing the program to run in verbose or silent mode using a flag.

Installation

jsfinder requires Go 1.20 to install successfully.Run the following command to get the repo :

go install -v github.com/kacakb/jsfinder@latest

Usage

To see which flags you can use with the tool, use the -h flag.

jsfinder -h

Flag	Description
-l	Specifies the filename to read URLs from.
-c	Specifies the maximum number of concurrent requests to be made. The default value is 20.
-s	Runs the program in silent mode. If this flag is not set, the program runs in verbose mode.
-o	Specifies the filename to write found URLs to. The default filename is output.txt.
-read	Reads URLs from stdin instead of a file specified by the -l flag.

Demo

I

If you want to read from stdin and run the program in silent mode, use this command:

cat list.txt| jsfinder -read -s -o js.txt

II

If you want to read from a file, you should specify it with the -l flag and use this command:

jsfinder -l list.txt -s -o js.txt

You can also specify the concurrency with the -c flag.The default value is 20. If you want to read from a file, you should specify it with the -l flag and use this command: