Players Can't see stretchx?

[i8bit]

So I was doing some tests and I found out that other players can't see the manipulation function of 'stretch'..

PHP Code:

//#CLIENTSIDE
function onKeyPressed(code, key){
 if (key == "z"){
  player.stretchx = -1;
  player.chat = "Reflection Test";
 }
} 


Obviously when you do it, you can see it on your screen.... But how do I set it so other players can see the manipulation too?