cookies not remembered between browser shutdown and browser restart.. :(

i have the following test script: <html> <body> <?php var_dump($_COOKIE);?> <script> document.write (document.cookie); document.cookie = 'abc=def'; </script> </body> </html> if you load it up, you get an empty page. if you then refresh the page, you get that abc cookie displayed. but if you close down the browser entirely and restart it, then view the script output again, it doesn't show the cookie that was set earlier. what am i doing wrong here? because this used to work just fine, then it suddenly stopped working in both firefox and chrome. i'm using ubuntu and lubuntu.