Javascript set unicode in textarea

Javascript set unicode in textarea

I have a text area that contains the unicode: (ãÑÍÈÇ ßíÝ ÍÇáß).
When I pass it to the CGI it URL encodes as:
%D9%85%D8%B1%D8%AD%D8%A8%D8%A7%20%D9%83%D9%8A%D9%81%20%D8%AD%D8%A7%D9%84%D9%83
I want to take this and set it as the value for the text area but I cannot
figure out how to convert the %D9%85... string back to (ãÑÍÈÇ ßíÝ ÍÇáß)