如何在不刷新整个页面和闪烁的情况下自动刷新iframe

So I am trying to make a chat room in html it is really basic but i would like to make the iframe i use to display my messages automatically refresh but without flikering how would i do that

i have tried

using this

window.setInterval("reloadIFrame();", 100);
function reloadIFrame() {
document.getElementById("commentsframe").src="http://billischill.ddns.net/chatfile.html";
}

but the whole iframe flikers when it refreshes and i cant have that

this here is my url

its pretty weird but i dont care i am trying to make it better

if you have any sugestions just leave it in the chat please