<!doctype html>
<html>
  <head>
    <title>horizontal alignment</title>
    <meta charset="utf-8"/>
  </head>
  <body>

    <!-- The MathML recommendation does not specify horizontal alignment of scripts. We apply the maximum vertical shifts necessary for all subscripts / superscripts. Here we need to shift the tall green scripts to avoid collision and so the red scripts will be shifted by the same distance. -->
    <math style="position: absolute;">
      <mspace height="100px" depth="100px"/>
      <mmultiscripts>
        <mn>0</mn>
        <mspace width="10px" height="50px" mathbackground="green"/>
        <mspace width="10px" depth="50px" mathbackground="green"/>
        <mspace width="10px" height="10px" mathbackground="red"/>
        <mspace width="10px" depth="10px" mathbackground="red"/>
        <mprescripts/>
        <mspace width="10px" height="10px" mathbackground="red"/>
        <mspace width="10px" depth="10px" mathbackground="red"/>
      </mmultiscripts>
    </math>

    <!-- These black rectangles should hide the top/bottom of the <mmultiscripts> element. So the red scripts should not be visible -->
    <math style="position: absolute; top: -40px;">
      <mspace height="100px" depth="100px"/>
      <mspace width="200px" height="40px" depth="20px" mathbackground="black"/>
    </math>
    <math style="position: absolute; top: +40px;">
      <mspace height="100px" depth="100px"/>
      <mspace width="200px" height="20px" depth="40px" mathbackground="black"/>
    </math>

  </body>
</html>
