window.onresize = function(){
docwidth = document.body.offsetWidth - 20;
docheight = document.body.offsetHeight - 20;
mainhandler.style.width = (docwidth / docheight) < 1680 / 1120 ? docwidth : docheight * 1680 / 1120;
mainhandler.style.height = (docwidth / docheight) < 1680 / 1120 ? docwidth * 1120 / 1680 : docheight;
}
window.onload = function(){
docwidth = document.body.offsetWidth - 20;
docheight = document.body.offsetHeight - 20;
mainhandler.style.width = (docwidth / docheight) < 1680 / 1120 ? docwidth : docheight * 1680 / 1120;
mainhandler.style.height = (docwidth / docheight) < 1680 / 1120 ? docwidth * 1120 / 1680 : docheight;
}