insert tags into textarea around any selection

[ivan52]

i have some problem please help if you can

i have one textarea, and user can type his info into this area
i make some buttons, that user can format his text
(like in this forum)

but here it is made so, that you need to write text into open.window

i want that tags will be insert by clicking button around any selection, and then shown in the same textarea already formated

[ivan52]

http://www.daveclarkconsulting.com/research/selected_text.html

it is quite good
i need something like this
but it works on DHTML Edit exec commands

how can i format text like in this wisiwyg editor with any special tag

for example i need insert p align=justify around selection
or tag big, or something else anything what i need
not only given in dhtml classes

[ivan52]

what i have find

JustifyCenter
Centers the format block in which the current selection is located.

JustifyFull
Not currently supported.

JustifyLeft
Left-justifies the format block in which the current selection is located.

JustifyNone
Not currently supported.

JustifyRight
Right-justifies the format block in which the current selection is located.

justify full is not supportet jet, but i need this option to format my text maybe can i something else????