Question

What is the point of doing this:

var resultsArray = (typeof response.d) == 'string' 
    ? eval('(' + response.d + ')') : response.d;

inside onSuccess() callback of $.(ajax) call?

Answer 1

var resultsArray =                  /* assign a value to resultsArray...        */
  (typeof response.d) == 'string' ? /* ...if the type of response.d is string   */
  eval('(' + response.d + ')')    : /* ...then evaluate it as if it was JS code */
  response.d;                       /* ...else just assign it unaltered         */