grid.js

let rows=100;
let cols=26;
let addressColCont = document.querySelector(".address-col-cont");
let addressRowCont = document.querySelector(".address-row-cont");
let cellsCont= document.querySelector(".cells-cont");
let addressBar= document.querySelector(".address-bar");
for(let i=0; i< rows; i++){
   let addressCol= document.createElement("div");
   addressCol.setAttribute("class","address-col");
   addressCol.innerText = i+1;
   addressColCont.appendChild(addressCol);
}

for(let i=0;i<cols;i++){
    let addressRow= document.createElement("div");
    addressRow.setAttribute("class", "address-row");
    addressRow.innerText = String.fromCharCode(65+i);
    addressRowCont.appendChild(addressRow);
}

for(let i=0;i<rows;i++){
    let cellsRow = document.createElement("div");
    cellsRow.setAttribute("class","cells-row");
    
    for(let j=0;j<cols;j++){
        let cell = document.createElement("div");
        cell.setAttribute("class","cell");
        cell.setAttribute("contenteditable" , "true");
        cell.setAttribute("rid",i);
        cell.setAttribute("cid",j);
        cell.setAttribute("spellcheck","false");
        eventListenerForCell(cell,i,j);
        cellsRow.appendChild(cell);
        
        
    }
    cellsCont.appendChild(cellsRow);
}

function eventListenerForCell(cell, i, j){
    cell.addEventListener("click", (e)=>{
        addressBar.value = `${String.fromCharCode(65+j)}${i+1}`
    })
}