If the page goes white, then that's typically a syntactical error. You can check your logs or enable error reporting with
You can poll for the result count as well:
printf('There are %d records returned.', sqlsrv_num_rows($_rs));
Before that while loop. That needs to have at least one record. If it shows 0 (and no error), that indicates that your query simply has no matching results.
The semi-colon must not be on the while loop. Since the property of it takes the last resultant, that makes the returned fetch to become null (or false). Therefore it will never enter the conditional block to assign the variables individually.