docs: function checkProperties(name){
    var bul=false; // boolean to control if its defined the property
  
    for(var i=0; i<properties.length; i++){//iterate over prop names
      if(properties[i] === name){//if it is
        bul=true;
      }
    }
    if(bul!==true){// it isn't finded the statement of the tag
      throw new Error('Not defined '+name);
      }  
  }