The content of the html page is not enough to fill the full screen and the footer is not displayed at the bottom

As shown in the picture.
You can use css media queries to configure the min-height of different bodies;
here is a dynamic setting with js:
jq:
$("#body").css("min-height",(document.documentElement.clientHeight- otherHeight)+'px');
The minimum height of the central content area can be obtained by subtracting other heights such as the header and footer from the height of the visible area of ​​the document.
Other frames take care of themselves.