- var_dump: documentation ( source)
- preg_match_all: documentation ( source)
<?php
$stylestr = 'text-align:center;display:block;';
$_style = array();
preg_match_all('#(.*?):(.*?);#', $stylestr, $matches);
foreach($matches[1] as $index => $key) $_style[$key]=$matches[2][$index];
//$_style = array_combine($matches[1], $matches[2]);
var_dump($_style);