$test doesn't have any value in the code you have posted here. Assuming $row is a string within an array of $row, then using $test would be the first letter of the value in $row.
$row = array('This is a string');
$test = $row;
print $test; //T
That's simply because a string is nothing more than a char array, so you can access a string letter by letter by accessing into it.
As for the JS, the only thing I can see being a problem PHP wise is if your string contains a ' within it which would damage the request for the american function call. Otherwise, assuming that $row is a valid array, everything looks fine. You can check your output HTML source to see what's in the <button> value and onclick attribute.