content.js

const shortTextForNumber = (number) => {
    if (number < 10000) {
        return number.toString()
    } else if (number < 1000000) {
        return Math.floor(number / 1000)
            .toString() + "k"
    } else {
        return Math.floor(number / 1000 / 1000)
            .toString() + "m"
    }
}

let div = document.createElement('div');
div.className = "rankrank0";
document.body.append(div);
let myhostname = null;
document.addEventListener("mouseover", (e) => {
    //console.log(e.target.closest('a'));
    let a = e.target.closest('a');
    if (a === null) return;
    let hostname = new URL(e.target.closest('a').href).hostname;
    if (hostname === '') return;
    myhostname = hostname;
    chrome.runtime.sendMessage({
        "hostname": hostname
    },
        (msg) => {
            if (msg.hostname !== myhostname) return;
            let rank = msg.rank;
            if (typeof rank === 'number') rank = shortTextForNumber(rank);
            div.innerHTML = 'S ' + rank;
        }
    )
});
document.addEventListener("mouseout", () => {
    div.innerHTML = "";
    myhostname = null;
});