Validation For e-mail Id

This code generates the valid output for an email. It is written for php but can be used in any language :-

function getmailvalid(){

$x=$_GET['email'];

$atpos=strpos($x,"@");

$dotpos=strripos($x,".");

if ($atpos<1 || $dotpos<$atpos+2 || $dotpos+2>=strlen($x)){

return 1;

}

else{

return 0;

}

}

$valideid=getmailvalid();