My code is in the attachment alex.txt.
When i press the button for first time it gives me error: 'null' is null or not an object. But when i press it again or refresh the page and press the button it gives me the result that i expect.
When i change the var pdbfile1,2,3 values(for example with 2x4n;3gis;1crn) and press the button again there is the error again and i have to refresh the page again.
Can you please help me to to resolve this problem.