javascript is design to run in browser,so you don't need any other programs rather than a browser,you can just write the script in any text editor and run it in browser's console.Of cause the tampermonkey or other script manager extension can make easier to manage how the scripts run in you browser and it have a good editor,otherwise if you want to run javascript without a browser you can use nodejs and code in vscode or other IDE witch provide better coding experience.You should rather read the the javascript development guides or tutorials than ask someone first
Need help
Okay, so Im new to javascript and I see the syntax is quite similar to Lua. Do I require any programs to make a userscript and use it(other than tampermonkey), and would somebody be willing to help me out? I have quite some questions if somebody is willing to help. I can send a link and you join the website so we can chat and script.