javascript: How do I properly loop this function?

Question

I am new to coding with js, and have tried many different ways to loop this code, as well as asking a friend of mine who is a bit more proficient than I am, and he was incorrect as well. I looked up how to use loops in js as well, and I seem to be stumped, so if you could also give me a basic explanation as to how loops in js work, that'd be great!

ORIGINAL CODE

function partA() {
var classes1 = document.getElementsByClassName('_jvpff _k2yal _csba8 _i46jh _nv5lf'); // finds follow button
var Rate1 = classes1[0];Rate1.click(); // clicks button1

}

setTimeout(partB, 20000); // begins func. B about 17 seconds after func a has been completed
function partB() {
var classes2 = document.getElementsByClassName('_de018 coreSpriteRightPaginationArrow'); // finds “next” arrow
var Rate2 = classes2[0];Rate2.click(); // clicks next arrow

}

partA(); // runs functions

The original code itself works fine, but it never seems to work with any loops I use.

Most Recent Loop Attempt - Note: failed, obviously

function partA() {
var classes1 = document.getElementsByClassName('_jvpff _k2yal _csba8 _i46jh _nv5lf'); // finds follow button
var Rate1 = classes1[0];Rate1.click(); // clicks button1

}

setTimeout(partB, 20000); // begins func. B about 17 seconds after func a has been completed
function partB() {
var classes2 = document.getElementsByClassName('_de018 coreSpriteRightPaginationArrow'); // finds “next” arrow
var Rate2 = classes2[0];Rate2.click(); // clicks next arrow

}

partA(); // runs functions

for (i = 0; i < 30; i++) {
text += “The number is ” + i + “<br>”;

}

Thank you in advance! - Michael

Any tips to just generally improve the code would also be appreciated.

Are you trying to have the functions call each other? What are you trying to achieve with your code? — Beamer180, Mar 21 '16 at 03:51
I was going to ask exactly what @Beamer180 asked above. An important part of asking questions on SO is to ask them clearly. — shashanka n, Mar 21 '16 at 03:52
Also, a couple of things: you are not using `text` anywhere, and you are using the wrong quotes (use `" "` not `“ ”`) — JCOC611, Mar 21 '16 at 03:54
@shashankan I'm trying to loop part A. part A then serves to start part B, but that doesn't really need changing. I need to figure out how to loop A. — Michael B, Mar 21 '16 at 03:55
@Beamer180 I'm trying to loop part A. part A then serves to start part B, but that doesn't really need changing. I need to figure out how to loop A. — Michael B, Mar 21 '16 at 03:55
@MichaelB If you're trying to loop part A, then why is the function call outside the loop? — shashanka n, Mar 21 '16 at 04:00
@shashankan Ah. Stupid mistake on my part. But what do I define " text " as? Sorry for my ignorance, heh. Teenager learning to code. — Michael B, Mar 21 '16 at 04:04
Seems like you're not really asking about how loops work, but more about how Javascript interacts with a HTML document. Start here: http://stackoverflow.com/questions/1533568/what-is-the-correct-way-to-write-html-using-javascript — Tibrogargan, Mar 21 '16 at 04:11
@Tibrogargan Thanks, I read it, and it helped somewhat, but I honestly need specific information on loops at the moment. — Michael B, Mar 21 '16 at 04:28
Maybe rephrase your question then. It's really not clear what you're trying to do. (Simulate pressing a button after 20 seconds ... but why do you need a loop to do that?) — Tibrogargan, Mar 21 '16 at 04:30
@Tibrogargan I am doing two things in this script, #1, I am clicking a button on a blog I am working on. After that, The script is supposed to click a second button to go to the next blog post, so I can test out my blog long-term, free-hands, theoretically while writing something to go along with my post. I want function partA to loop, and partA itself causes the rest to loop. — Michael B, Mar 21 '16 at 04:38

Tibrogargan · Accepted Answer · 2016-03-21T05:12:35.900

Still can't work out exactly what you're after (looks like: trying to automate some repetitive task in some page for which you don't control the source)

<!DOCTYPE html>
<html>
<head>
<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.12.0/jquery.min.js"></script>
<title>JS Loop Example?</title>
<script>
function foo() {
    var div = $("#x")[0];
    div.innerHTML = "foo was clicked";
    for (i = 0; i < 5; i++) {
        div.innerHTML += "<br />!";
    }
    setTimeout(function(){ $('.barButton').click() }, 3000)
}
function bar() {
    var div = $("#x")[0];
    while (div.firstChild) {
        div.removeChild(div.firstChild);
    }
    var wibble = document.createTextNode('bar was clicked');
    div.appendChild(wibble);
    for (i = 0; i < 5; i++) {
        div.appendChild(document.createElement('br'));
        wibble = document.createTextNode('?');
        div.appendChild(wibble);
    }
    setTimeout(function(){ $('.fooButton').click() }, 3000)
}
</script>
</head>
<body onload='setTimeout(foo, 3000)'>
<script>
// Up until the close of the body, I can just write into the document.
document.write('<div id="x" class="stuffGoesHere">');
document.write('some random text<br />');
for (i = 0; i < 5; i++) {
    document.write('#<br />');
}
document.write('</div>');
document.write('<input type="button" class="fooButton" value="foo" onClick="foo()" />');
document.write('<input type="button" class="barButton" value="bar" onClick="bar()" />');
</script>
</body>
</html>

javascript: How do I properly loop this function?

1 Answers1