code: function(elem, other_elems) {
                      // Pairwise overlap detection
                      var overlapping = function(a, b) {
                          if (Math.abs(2.0*a.offsetLeft + a.offsetWidth - 2.0*b.offsetLeft - b.offsetWidth) < a.offsetWidth + b.offsetWidth) {
                              if (Math.abs(2.0*a.offsetTop + a.offsetHeight - 2.0*b.offsetTop - b.offsetHeight) < a.offsetHeight + b.offsetHeight) {
                                  return true;
                              }
                          }
                          return false;
                      };
                      var i = 0;
                      // Check elements for overlap one by one, stop and return false as soon as an overlap is found
                      for(i = 0; i < other_elems.length; i++) {
                          if (overlapping(elem, other_elems[i])) {
                              return true;
                          }
                      }
                      return false;
                  }
docs: Helper function to test if an element overlaps others