"content_scripts": [{
        "matches": ["ваш-урл-или-*-маска"],
        "js": ["contentscript-min.js"]
    }]

<?php
$rf= mysql_query("SELECT * FROM `zRestoran` WHERE idrest='$id' and data='$data' and time='$time'");
$nums = [];
while($row = mysql_fetch_assoc($rf)) {
  $nums[] = $row['nomer']; 
}

for( $x = 1; $x <= 20; $x++ ) {
  <input type="checkbox" <? if (in_array($x, $nums)) echo 'disabled="disabled"'; } ?> name="stolik[]" value="<?= $x ?>"><?=$x ?>
} 
 ?>

cp -av test1/* test2/
«test1/file» -> «test2/file»
«test1/test3» -> «test2/test3»