for (var i = 0; i < this.skill.trainings.length; ++i) {
            if (this.skill.trainings[i].URL == undefined) trainingNames += this.skill.trainings[i].name + ', ';
            else trainingNames += "<a href = '" + this.skill.trainings[i].URL + "'>" + this.skill.trainings[i].name + '</a>, ';
        }