CODE EXAMPLE FOR HTML

how to make html element center of the screen

// Replace X and Y with a number and u with a unit. do calculations
 // and remove parens
.centered_div {
   width: Xu;
   height: Yu;
   position: absolute;
   top: 50%;
   left: 50%;
   margin-left: -(X/2)u;
   margin-top: -(Y/2)u;
}