It seems that the WYSIWYG editor (the one you get when you select HTML with editor) inserts HTML that does not work with all browsers.

The editor inserts this:

A CO<span class="Apple-style-span">2</span>-filled balloon

which renders as this:

A CO2-filled balloon

Instead you should the non-WYSIWYG editor that is not the plain-text editor (that is, we want to use the editor you get when we select HTML). Now go to where you want to add a subscript and add <sub> tags (for superscripting use the <sup> tags), like this:

A CO<sub>2<sub>-filled balloon

Should render like this:

A CO₂-filled balloon

So far whenever I edit HTML using the “plain text” editor iSites seems to want to translate the angle brackets into their entity values, so that when you go to view the HTML the code is visible.

For example, if I enter this into the editor:

<div><p>hello</p></div>

then when I go to view it I see:

<div><p>hello</p></div>

instead of:

hello

This may be happening because when the user saves the entry, the tool parses the input text as XML instead of plain text? I remember having a similar problem when I tried to roll my own HTML editor.

Anyway, the moral of the story is stay away from the plain text editor, use the regular HTML editor instead.