How to: Perform an AJAX Synchronous request

From the Jquery docs: you specify the async option to be false to get a synchronous Ajax request. Then your callback can set some data before your mother function proceeds.

Here's what your code would look like if changed as suggested:

beforecreate: function(node,targetNode,type,to) {
    jQuery.ajax({
         url:    'http://example.com/catalog/create/' 
                  + targetNode.id 
                  + '?name=' 
                  + encode(to.inp[0].value),
         success: function(result) {
                      if(result.isOk == false)
                          alert(result.message);
                  },
         async:   false
    });          
}