An example of a complex function

complex-function.js

function startProgram() {
  if (!window.indexedDB) {
    window.alert("Browser not support indexeDB");
  } else {
    let openRequest = indexedDB.open("store", 1);
 
    openRequest.onupgradeneeded = () => {};
 
    openRequest.onerror = () => {
      console.error("Error", openRequest.error);
    };
 
    openRequest.onsuccess = () => {
      let db = openRequest.result;
    };
 
    document.getElementById('stat-op').addEventListener('click', () => {});
    document.getElementById('pre2456').addEventListener('click', () => {});
    document.getElementById('cpTagList100').addEventListener('change', () => {});
    document.getElementById('cpTagList101').addEventListener('click', () => {});
    document.getElementById('gototop').addEventListener('click', () => {});
    document.getElementById('asp10').addEventListener('click', () => {});
 
    fetch("employeList.json")
      .then(res => res.json())
      .then(employes => {
        document.getElementById("employesSelect").innerHTML = employes.reduce(
          (content, employe) => employe.name + "<br>",
          ""
        );
      });
 
    document.getElementById("usernameLoged").innerHTML = `Welcome, ${username}`;
  }
}