The effect achieved in this article is that according to the different browser resolutions, the background color at the bottom of the page adapts to the browser height, which means that the background color can be automatically filled.
function height_adaptive(){
var main=$(document).height();
var title= document.getElementById("login_title").scrollHeight;
var body=document.getElementById("login_body").scrollHeight;
var bottom=main-title-body;
$("#login_bottom") .height(bottom);
}