How to get height of entire document with JavaScript?

Question

Some documents I can\'t get the height of the document (to position something absolutely at the very bottom). Additionally, a padding-bottom on seems to do nothing on these

Answer 1

use blow code for compute height + scroll

var dif = document.documentElement.scrollHeight - document.documentElement.clientHeight;

var height = dif + document.documentElement.scrollHeight +"px";