How to edit RTF strings directly in the browser

What I currently have:
C# / ASP.NET web application that contains text areas displaying RTF strings similar to the example below.

What I need to accomplish:
I need to edit the RFT string as if it were in Wordpad. Examples would be adding a tab, changing text color or changing the font. This needs to be accomplished inside of the web browser.

How I currently edit the RTF string:

[]Copy the RTF code to Notepad and save it with a RTF extension.
]Open the file in Wordpad.
[]Make/Save my changes.
]Open the file in NotePad
[*]Copy/paste the new RTF string back to the browser.

The RTF strings are sent to printers, so using HTML is not an option. I am at a loss on how to make this happen. Your input would be appreciated.

Example RTF String:

{\\rtf1\\ansi\\deff0{\\fonttbl{\\f0\\fnil Courier;}{\\f1\\fnil\\fcharset0 Courier;}}
{\\colortbl ;\\red155\\green187\\blue89;\\red255\\green0\\blue0;\\red0\\green0\\blue0;}
{\\*\\generator Msftedit;}\\viewkind4\\uc1\\pard\\sa200\\sl276\\slmult1\	x720\	x1440\	x2880\	x5760\\cf1\\lang9\\f0\\fs24 This line is the \\lang1033\\f1 Green\\lang9\\f0  color\\cf0\\line\	ab this line has 1 tab\\line\	ab\	ab this line has 2 tabs\\line\	ab\	ab\	ab this line has 3 tabs\\line\	ab\	ab\	ab\	ab this line has 4 tabs\\line\\cf2\	ab This line is red and has a tab before it\\line\\cf3\\page\\par
\\pard\	x1440\	x2880 This line is the default color and the first line on page 2\\line\	ab\	ab This is the second tab on the second line on the second page\\line\\page\\par
\\pard This is the third page with formatting examples\\line\\fs30 First line with 15 point text\\line\\fs20 Second line with 10 point test\\line\\i Italics on \\i0 Italics off\\line\\b Bold on \\b0 Bold off\\line\\scaps Small Caps On \\scaps0 Small Caps Off\\line\\strike Stike through on \\strike0 Strike Off\\line\\caps All Capitals On \\caps0 All Capitals Off\\line\\outl Outline on \\outl0 Outline Off\\line\\ul Underline on \\ulnone Underline Off\\line\\uldb Double Underline on \\ulnone Double Underline Off\\line\\ulth Thick Underline on \\ulnone Thick Underline Off\\line\\ulw Underline words only on \\ulnone Underline words only off\\line\\ulwave Wave Underline on \\ulnone Wave underline off\\line\\uld Dotted Underline on \\ulnone Dotted underline off\\line\\uldash Dash Underline on \\ulnone Dash underline off\\line\\uldashd Dot Dash Underline on \\ulnone Dot Dash underline off\\par

A plugin is probably the best approach for this. You can do it with Winforms, but if you need it in an ASP.NET application then I’d look into something like this.