There is an optional third parameter to str_pad( ) that lets you set the padding character to use

 
<?
    $string = "Goodbye, Perl!";
    $newstring = str_pad($string, 10, 'a');
?>

1.	str_pad() function pads string to length pad_length with a specified characters
2.	str_pad-2.php
3.	str_pad.php
4.	string str_pad ( string input, int length [, string padding [, int type]] )
5.	Make use of str_pad()'s optional parameters
6.	STR_PAD_LEFT, STR_PAD_RIGHT, or STR_PAD_BOTH:
7.	Using left space padding
8.	Using left zero padding

There is an optional third parameter to str_pad( ) that lets you set the padding character to use : str_pad « String « PHP