var firstDiv=document.getElementById("firstDiv");
var initialHeight = firstDiv.clientHeight;
// var initialWidth = firstDiv.clientWidth;
var possibleNewHeight = window.innerHeight;
// var possibleNewWidth = window.innerWidth;
var finalHeight = 0;
if (possibleNewHeight>initialHeight){
  finalHeight = possibleNewHeight;
} else {
  finalHeight = initialHeight;
}

// alert(finalHeight);

// if (finalHeight>670){
  // finalHeight=450;
// }
  
firstDiv.style.height=finalHeight+"px";


document.getElementById("firstDiv").style.marginTop  = (-30).toString() + "px"

// firstDiv.style.position="relative";
// firstDiv.style.left=-(possibleNewWidth-initialWidth)/2+30+"px";
// firstDiv.style.width=possibleNewWidth-20+"px";

//

// var works1 = document.getElementById("height");
// works1.style.background="blue";
// var works2 = document.getElementById("works2");
// var works1heigh = works1.clientHeight;
// var works2heigh = works2.clientHeight;

// alert(works1heigh+" ; "+works2heigh)

// if (works1heigh>works2heigh){
  // works2.style.height=works1heigh+"px";
// }else{
  // works1.style.height=works2heigh+"px";  
// }