javascript - How to return a value from a function that calls $.getJSON?

Question

function lookupRemote(searchTerm)
{
   var defaultReturnValue = 1010;
   var returnValue = defaultReturnValue;

   $.getJSON(remote, function(data)
   {
      if (data != null)
      {
           $.each(data.items, function(i, item)
           {
               returnValue = item.libraryOfCongressNumber;
           });
      }
    });
    return returnValue;
}

Why is the returnValue from this function alway equal to the default value set at the beginning of the function and never to the value retrieved from the JSON lookup?

Answer 1

If you don't want to use asynchronous function, better use the following:

function getValue(){
   var value= $.ajax({ 
      url: 'http://www.abc.com', 
      async: false
   }).responseText;
   return value;
}

This function waits until the value is returned from the server.