function EmailIsValid($email){
        
		$boolean_flag;
		$struct_validation = filter_var($email, FILTER_VALIDATE_EMAIL);
		
		$domain_validation = false;
		
	    $atIndex = strrpos($email, "@");
    	$domain = substr($email, $atIndex+1);

    	if(!checkdnsrr($domain,"MX"))
    	{ 
	        $domain_validation = false;
	    }
	    else { $domain_validation = true; }
		
		if(!$struct_validation || !$domain_validation) { $boolean_flag = false; }
	    else { $boolean_flag = true; }
		
		echo "boolean_flag = ".$boolean_flag;
		return $boolean_flag;
    }