after submitting, working with data on same page

I have my two html textarea fields followed by these two buttons. <form action="<?=$_SERVER['PHP_SELF']?>" method="post"> <br> <input type="submit" name="calcentry" value="Calc Your Entry" /> <input type="submit" name="clearentry" value="Clear Your Entry" /> </form> I have textarea1 to type words into. I have textarea2 for my results. I have people type words in textarea1 and after hitting the "calcentry" button I want to reload the same page, go into my: if ($calcentry) {...} part of my code and do some calculations with php and mysql and put my output into textarea2. But after submitting and re-loading the page my textarea1 field is empty. So my first question is how do I keep the data in textarea1 so when I perform my submit I can do some calculations on it etc? Then how can I place my results into textarea2. So all I want is to type words into a textarea field, reload the same page, do some calcs on these words, and place the results into textarea. So it amounts to having the exact same page but now I have my calculated results in the second textarea. I have all my code for calcs etc. and it works fine. Thanks for any help, Doug