Использование setInterval() и функция не определена ошибка

Question

В моем приложении мне нужно периодически вызывать функцию, для этого я использую функцию setInterval() javascript. Однако по какой-то причине он дает ошибку, которая функционирует так, как она не определена. Мой код JS приведен ниже: -

var choice; //counts how many choices have been made 
choice = 0; 
var choice1; //stores index of first card picked 
var choice2; //stores index of second card picked 
var choice3; //stores index of third card picked 
var choice4; //stores index of fourth card picked 
var counter = 0;  //counts matches made 
var numAttempts = 0; //counts attempts made 
var backcard ="img/nyaa.png"; //shows back of card when turned over 
var numOfMatches= 3; 
var faces = []; //array to store card images 
faces[0] = 'img/bub.jpg'; 
faces[1] = 'img/bub.jpg'; 
faces[2] = 'img/mustache.jpg'; 
faces[3] = 'img/mustache.jpg'; 
faces[4] = 'img/bub.jpg'; 
faces[5] = 'img/bub.jpg'; 
faces[6] = 'img/hover.jpg'; 
faces[7] = 'img/hover.jpg'; 
faces[8] = 'img/hover.jpg'; 
faces[9] = 'img/hover.jpg'; 
faces[10] = 'img/mustache.jpg' ; 
faces[11] = 'img/mustache.jpg'; 


/* Responds to click on a table cell indicating card selected */ 
function choose(card) { 


if (choice===0) { //if first pick, identify card selected 
    choice1=card; 
    document.images[card].src = faces[card]; 
    choice = 1; //one pick made 
// console.log(choice1); 
    } 
if 
    (choice === 1){ //second pick, identify card selected 
    choice2 = card; 
    document.images[card].src =faces[card]; 
    choice=2; 
    //console.log(choice2); 
    return choice2; 
    } 
if 
    (choice === 2){ //third pick, identify card selected 
    choice3 = card; 
    document.images[card].src =faces[card]; 
    choice=3; 
    //console.log(choice3); 
    return choice3; 
    } 
    else 

    choice =4; { //fourth pick, identify card selected 
    choice4 = card; 
    document.images[card].src =faces[card]; 
    choice=4; 
    //console.log(choice4); 
    tid=setInterval("checker()",1000); //use timer to pause so user can see selections 
    return choice4; 
} 

/* Checks to see if a match is made */ 
function checker() { 
clearInterval(tid); //stops timer 
numAttempts++; //adds 1 to attempts 
document.getElementById("attempts").innerHTML = numAttempts; //display number of attempts 
if (faces[choice1] === faces[choice2]=== faces[choice3] === faces[choice4]) { //if a match is selected 
    counter++; //adds an increment to matches 
    if (counter === numOfMatches) { //if matches made = maximum possible matches, display message 
      alert("You won.\n It took you " + numAttempts + " tries.\n Refresh the page or press restart to play again."); 
     } 
    choice = 0; 
     return ; 
    } 
    else { //if no match made, turn cards back over 
    document.images[choice1].src = backcard; 
    document.images[choice2].src = backcard; 
    document.images[choice3].src = backcard; 
    document.images[choice4].src = backcard; 
    choice = 0; 
    return ; 
     }  
} 
faces = shuffle(faces); 
function shuffle(dealer){ 
function shuffle() {} 
    for(var j, x, i = dealer.length; i; j = Math.floor(Math.random() * i), x = dealer[--i], dealer[i] = dealer[j], dealer[j] = x); 
    return dealer; 
     }; 
function reset(){ 
    location.reload(); //restarts page and game 
}} 

Любая помощь будет принята с благодарностью!

Answer 1

Это просто неправильный способ использования setInterval();.

Удалить скобки из "checker".

setInterval("checker",1000); 

или использовать затворы.

setInterval(function(){checker()},1000); 

Кроме того, вы, возможно, хотели разместить choice=4; внутри квадратных скобок (тот после else).

else{ 
    choice =4; 
    //fourth pick, identify card selected 
    choice4 = card; 
    ...