/* from https://stackoverflow.com/questions/38217274/loading-gif-on-normal-form-submit */
#pageloader
{
  background: rgba( 255, 255, 255, 0.8 );
  display: none;
  /* height: 100%;*/
  left: 50%;
  position: fixed;
  width: 100%;
  z-index: 9999;
  top: 50%;
  right: auto; 
  bottom: auto;  
  transform: translate(-50%, -50%);
 
}

#pageloader img
{
  left: 50%;
  margin-left: -32px;
  margin-top: -32px;
  position: absolute;
  top: 50%;
}