相关疑难解决方法(0)

我有这个柜台,但是我希望它能永远运行,这很简单,我在这里做错了什么？

function timer() {
  console.log("timer!")
}

window.setInterval(timer(), 1000)

我有以下JS函数:

function checkIfGameAlreadyStarted(){
    $.get("IsGameAlreadyStarted",null,function(gameAlreadyStarted){
        if (gameAlreadyStarted == "true"){
            window.location = "index.jsp?content=game";       
        } else{
            alert("bla");
        }  
    });
}

function joinGame(playerForm){
    $.get("GenerateClientID",null,function(clientID){         
        $.get("JoinGame",{
            "NAME" : playerForm.elements[0].value,
            "ID" : clientID
        }
        ,function(gameParam){

            $("#waitingContainer").append("You have joined the game!<br\>Waiting for game creator to start game..");
            setInterval(checkIfGameAlreadyStarted(), 1000);    

        });
    });
}

为什么只setInterval执行checkIfGameAlreadyStarted一次,而不是每秒执行一次？