function fnScaleFactorX() {
   nScaleFactor = screen.deviceXDPI / screen.logicalXDPI;
   return nScaleFactor;
}
if (fnScaleFactorX() > 1) {
   document.getElementById("block_1").style.marginBottom = "-26000px";
   document.getElementById("block_2").style.marginBottom = "-26000px";
   document.getElementById("block_3").style.marginBottom = "-26000px";
}