Filtering markers on google map by WordPress category[SOLVED]

Solved, the problem was in filterMarkers() function

filterMarkers = function (category) {  
var markers = gmarkers[i];
for (var i = 0; i < gmarkers.length; i++) {

    // If is same category or category not picked
    if (gmarkers[i].category == category || category.length === 0) {  

      gmarkers[i].setVisible(true);
    }

    // Categories don't match 
    else { 
       gmarkers[i].setVisible(false);
    }
  }
}