Event.observe( window, 'load', function()
{
    if( $( 'valentin' ) != null )
    {
        Event.observe( $( 'n' ), 'keypress', just_numbers );
        Event.observe( $( 'p' ), 'keypress', just_numbers );
        Event.observe( $( 'valentin_form' ), 'submit', function( e )
        {
            e.stop();
            $( 'valentin_eredmeny' ).innerHTML = ( $( 'n' ).value > 0 && $( 'p' ).value > 0 ) ? Math.round( ( ( $( 'n' ).value - $( 'p' ).value ) * 0.368 + $( 'p' ).value * 1 ) * 10 ) / 10 : '?';
        } )
    }
} );

function just_numbers( e )
{
    var keyCode, selection;
    if( !e.keyCode && e.charCode ) keyCode = e.charCode;
    else if( !e.charCode && e.keyCode ) keyCode = e.keyCode;
    else keyCode = e.keyCode;
    selection = typeof e.currentTarget != 'undefined' ? ( e.currentTarget.selectionStart == e.currentTarget.selectionEnd ) : true   ;
    if( keyCode != 0 && keyCode != 8 && keyCode != 9 && keyCode != 13 && keyCode != 27 && ( ( "0123456789" ).indexOf( String.fromCharCode( keyCode ) ) == -1 || ( e.target.value.length > 1 && selection ) ) ) e.stop();
}