Tricky characters in dynamic textarea

i’m loading a txt file inside an html-enabled textarea. although i’m having problem displaying some characters, like <, +, %, >…
i replaced % with it’s escape equivalent (%25) and this woked. the > sign works just fine. the < sign doesn’t work at all, even when trying to escape it with <
the plus sign behaves the same as <. i’ve used its hex equivalent etc but nothing…
can you enlighten me?