Javascript Memory

Question

I was wondering why my program crashes after its made its first match....any ideas would be greatly appreciated. Below is the code snippet. Thanks for the input!

var clicks = 0; //counts how may picks have been made in each turn
var firstchoice; //stores index of first card selected
var secondchoice; //stores index of second card selected
var match = 0; //counts matches made
var backcard = "deck.jpg"; //shows back of card when turned over

var faces = []; //array to store card images
faces[0] = 'pic1.jpg';
faces[1] = 'pic2.jpg';
faces[2] = 'pic3.jpg';
faces[3] = 'pic3.jpg';
faces[4] = 'pic2.jpg';
faces[5] = 'pic1.jpg';

function choose(card) {
        if (clicks === 2) {
            return;
        }
        if (clicks === 0) {
            firstchoice = card;
            document.images[card].src = faces[card];
            clicks = 1;
        } else {
            clicks = 2;
            secondchoice = card;
            document.images[card].src = faces[card];
            timer = setInterval("check()", 1000);
        }
    }
    /* Check to see if a match is made */

function check() {
    clearInterval(timer); //stop timer
    if (faces[secondchoice] === faces[firstchoice]) {
        match++;
        document.getElementById("matches").innerHTML = match;
    } else {
        document.images[firstchoice].src = backcard;
        document.images[secondchoice].src = backcard;
        clicks = 0;
        return;
    }
}

firstchoice and secondchoice do not has default value. try with default value and let me know th eresult — Dirty Developer
– Dirty Developer, Commented Feb 17, 2017 at 21:02
It is a javascript code that checks to see if 2 clicked images match. If they match the cards will stay face up, and if they dont they will return to face down position.... I have also tried to set both default value to 0 and the program still does not respond after the first match — Ric SSalvacion
– Ric SSalvacion, Commented Feb 17, 2017 at 21:07

rasmeister · Accepted Answer · 2017-02-17 21:24:29Z

1

The first parameter of setInterval needs to be a function not a string pretending to be a function. So you would want this:

timer = setInterval(function() { check(); }, 1000);

Of course, you can simplify:

timer = setInterval(check, 1000);

Not sure why you're using setInterval() here. You could more easily just do:

timer = setTimeout(check, 1000);

The advantage is there is no interval to clear in the check() function.

The other issue is that you are not resetting your 'clicks' counter to 0 when there is a match.

You want this:

function check() {
    clearInterval(timer); //stop timer
    if (faces[secondchoice] === faces[firstchoice]) {
        match++;
        document.getElementById("matches").innerHTML = match;
    } else {
        document.images[firstchoice].src = backcard;
        document.images[secondchoice].src = backcard;
    }
    clicks = 0;
}

edited Feb 17, 2017 at 21:24

answered Feb 17, 2017 at 21:12

rasmeister

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1 Comment

Ric SSalvacion Over a year ago

Thanks everyone for your help, big shoutout to Rasmeister for debugging this problem!

Chad Fisher · Accepted Answer · 2017-02-17 21:15:48Z

0

I think you have to declare you timer function globally. Its only defined in the scope of the first function, so in the second when you try to clear it nothing happens:

var timer = ''; //Declare timer up here first!

function choose(card) { ... }

function check() { ... }

answered Feb 17, 2017 at 21:15

Chad Fisher

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1 Comment

Ric SSalvacion Over a year ago

var timer=''; var firstchoice=0; //stores index of first card selected var secondchoice=0; //stores index of second card selected I have now added default value and declared timer variable but still the same issue. Thanks for the comments by the way guys

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