javascript to check css element

[benanderson_475]

I have some simple JavaScript to hide/show images based on group address, 
how can i check css element before making next change like the below.
Many Thanks

Code:

$(function(){
  grp.listen('1/1/1', function(object, state) {
     if (state == 'value' && object.value == true) {
     //Check if css element .hidebyknx is shown then continue    
     $(".hidebyknx").addClass("hide");
     } else if (state == 'value' && object.value == false) {
         $(".hidebyknx").removeClass("hide");
     }
  }, true);
});