i was wondering if anyone could explain what the lines in bold mean. i don't understand what $data . = does

function RandomNumber($length)
{
$Random = srand((double)microtime()*1000000);

$data = "AbcDE123GHIJK4LMN567QRSTU89VWXYZ";
$data .= "aBCdefghijklmn123opq45rs67tuv89wxyz";
$data .= "0FGH45OP89";

for($i = 0; $i < $length; $i++)
{
$Random .= substr($data, (rand()%(strlen($data))), 1);
}
echo "$Random <br>";
}
RandomNumber(8);

Thanks,

Scoobie

it concatnates the value to the right of the variable name, $data, to the existing value of $data.
e.g.

$data = "first"
echo $data; //(will print: first)
$data .= "second"
echo $data; //will print: firstsecond)
$data .="third"
echo $data; //will print: firstsecondthird)

thats the basic idea. I am pretty sure you can also do

$data = $data + "second" + "third";

to acheive the same thing.

Just a small thing, but if you called that RandomNumber() function more than once you would get non-random (predictable) results. Don't call srand() more than once in a script. Ever. Its a very, very bad idea.