// JavaScript Document
var myHeight = 0;
if( typeof( window.innerWidth ) == 'number' ) {
  //Non-IE
  myHeight = window.innerHeight;
} else if( document.documentElement && ( document.documentElement.clientWidth || document.documentElement.clientHeight ) ) {
  //IE 6+ in 'standards compliant mode'
  myHeight = document.documentElement.clientHeight;
} else if( document.body && ( document.body.clientWidth || document.body.clientHeight ) ) {
  //IE 4 compatible
  myHeight = document.body.clientHeight;
}
          
d = document.getElementById("topofthepage");
topPos = d.offsetTop;
if ((topPos + document.getElementById("header").offsetHeight )>myHeight) {
  document.write('<a href="#top">Az oldal tetejére</a>');
}