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？