How to communicate with Wolfram alpha with webread()?

Sample case (where we want to know difference between the resuls):

s=sind(5);
diff=webread(sprintf("https://www.wolframalpha.com/input/?i=%.44g-sin(5)",s))

The results seem to come out, but it looks I could not get it as a variable…
Maybe should check the WFA docs also or something.