custom exception type javascript

    
function UserException(message){
    this.name = "UserException"; //constructor
    this.message = message || ""; 
    /**
    * constructor 
    * if (message is undefined) this.message = ""; 
    * else this.message = message;
    */  

    this.getMessage = function(){
        return this.message;
    }

    this.getName = function(){
        return this.name;
    }

    this.toString = function(){
        return this.name;
    }
}

try{
    throw new UserException("test user exception");
}catch(ex){
    console.log(ex);
    console.log(ex.toString());
    console.log("excetion name : " + ex.getName());
    console.log("exception message : " + ex.getMessage());

    if(ex instanceof UserException){
            console.log("exception type is UserException");     
    }
}