Beräknar snittet av betygen från antagnig.se https://www.antagning.se/se/mypages/credentials

betygsnitt_userscript.js

// ==UserScript==
// @name        Merit
// @description Beräkna din merit
// @match       https://*.antagning.se/se/mypages/credentials
// ==/UserScript==

'use strict';
const appendGrade = (gradeParam) => {
  const injectionPoint = document.querySelector('[data-protractor-upsec-approved-points-4teinf]')
  let gradeElement = document.createElement('p')
  gradeElement.textContent = `Merit: ${gradeParam.toFixed(2)}`
  injectionPoint.appendChild(gradeElement)
}

/**
 * @return {number}
 */
const calc = () => {
  const grades = {
    'A': 20,
    'B': 17.5,
    'C': 15,
    'D': 12.5,
    'E': 10,
    'F': 0
  };

  const subjects = document.querySelector('tbody').children
  const merit = 2.0
  const totalPoints = 2400
  const gradeIndex = 2
  const pointIndex = 3
  var total = 0

  Array.from(subjects, element => {
    let grade = element.children.item(gradeIndex).textContent
    let point = element.children.item(pointIndex).textContent
    total += grades[grade] * point
  });

  var final = total / totalPoints + merit
  console.log(`Din merit är: ${final}`)
  appendGrade(final)
};

(() => calc())()