SOURCE

const count = 100000;

function pageRender(total, pageIndex, size) {

    setTimeout(() => {
        for (let i = 0; i < size; i++) {
            const el = document.createElement("div");
            el.style.background = "#ccc";
            el.innerText = `第${(pageIndex-1) * size + i}个`;
            document.body.appendChild(el);
        }
        if(pageIndex < total){
            pageRender(total, pageIndex+1, size);
        }
    }, 0);

}

function append() {
    const size = 1000;
    const total = Math.ceil(count / size);
    pageRender(total, 1, size);
}

<button onclick="append()">change</button>