function pesquisa(parametro){
location.href="bnoticias.php?p="+parametro;
}
function cnenter(event) {
var keynum;
if(window.event) { //IE
            keynum = event.keyCode
} else if(event.which) { // Netscape/Firefox/Opera
            keynum = event.which
}
if( event.keyCode==13 ) { <!-- 13 é o código do Enter -->
             pesquisa(document.getElementById('ppesquisa').value);
}
}