//guide:
//1) login to salesforce
//2) open dev tools console
//3) execute "pre-start script" in dev tools console
//4) in "useful script" replace ObjectApiName to your object name
//5) execute "useful script" in dev tools console

//pre-start script
document.write('<script src="/soap/ajax/44.0/connection.js" type="text/javascript"></script><script src="/soap/ajax/44.0/apex.js" type="text/javascript"></script>')
var __sfdcSessionId = document.cookie.split('; ').find((item) => {return item.indexOf('sid=') == 0}).substring(4)