Javascript trouble understanding IF loop to use in a script

Question

I'm new at javascript and am using tampermonkey for a website. What i want to do is monitor a variable on a page and when said variable reaches a certain value, go to another page, do something, and then recheck the value of this variable.

My logic was to:

setInterval(function(){reloadPage1},10000);
var variable = someTextonThisPage;
if(someTextonthisPage meets condition)
{
    go to Page2;
    execute something on page 2;
    setNewValueForVariable; //(or just go back to initial 
    //and get the new value from there)
}

Now my problem is when the if executes, it goes to page2 keeps looping the if call even if i set the variable to something false.

I tried doing something like:

function doThis()
{
   if(condition)
      return true;
   else return false;
}

if(doThis())
{
    goToPage2;
    do stuff;
    doThis();
}

I end up having the if statement go on and on, going to page 2 and my settimeouts to do something on that page never execute because of the next iteration of the 'if'.

What am i doing horribly wrong in my thought pattern?

Answer 1

Your doThis() function is right. Everything ok with it.

function doThis()
{
    if(condition)
        return true;
    else 
        return false;
}

But when you check the loop you have to call it one time only. After doing stuff you are again calling doThis() function it is wrong.

if(doThis())
{
    goToPage2;
    do stuff;
    //doThis();
}

And also it depends on how you are calling this loop and functions.

For eg.,

<script>
    var i = 0;
    onPageLoad()
    {
        if(i%2==0){
            return true;
            i++;
        }else{
            return false;
            i++;
        }
    }

    if(onPageLoad()){
        goToPage2;
        doStuff();
    }else{
        onPageLoad()
    }
</script>

Here when the condition meets the right statement which is i%2 == 0 it will automatically call goToPage2 function otherwise it again going to check the condition.

You can add interval/timeout in the loop to check when the variable is updating and when it calls goToPage2 function.

Hope this helps.