Javascript "if" not working, ends in random loop

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This javascript code i have doesnt seem to work. Im new to javascript and orignally tried to avoid it and learned php instead... shouldve just learned it...

JavaScript

var status;
var miles = 2000;
var togo = 2000;
var day = 1;
var interval;
//Miles, day, and togo are normally constantly changing.
function checkstatus(){
	if(miles == 2000){
		clearInterval(interval); //It doesnt even get here
                document.getElementById("status").innerHTML="Status: At the place!";
		alert("You've reached the place!!");
		}
        }

function wGo(){
	clearInterval(interval);
	document.getElementById("status").innerHTML="Status: Moving";
	interval = setInterval(function(){checkstatus();},5000);
}

Tried it on my browser my other browser and js fiddle and my mouse ends up blinking for a while.

Posted 18-Nov-13 14:53pm

G4mm4R4y

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Comments

Sergey Alexandrovich Kryukov 18-Nov-13 21:51pm

This is of course not because "'if' is not working"... :-) It's a pretty bad idea to start your question with an apparently false statement.

You can execute this function under debugger and see what's going on. But the whole idea is quite bad. At least don't hard-code the constants, especially in two different places. Think what happens if you decide to change 2000 into something else.
If you explain your goal, we would probably help you...

—SA

G4mm4R4y 18-Nov-13 22:04pm

I meant to reply, see comment below

G4mm4R4y 18-Nov-13 21:57pm

The goal is to alert the user when his mileage goes up to 2000. It checks the mileage every 5 seconds. I thought this is the proper way to layout if statements?

ZurdoDev 18-Nov-13 22:01pm

1. Reply to the comment so that the user is notified.
2. Where do you call it every 5 seconds?
3. Put a breakpoint on line 1 of checkstatus() and see what happens.

G4mm4R4y 18-Nov-13 22:03pm

I thought I did reply, I apologize to Sergey and will reply. I can't check the code at the moment.

Sergey Alexandrovich Kryukov 18-Nov-13 23:10pm

First of all, never repeat anything. If it's written 2000, it should be written only once.
Avoid using functions with using variables from out scope, pass everything in parameters.
Also, you will repeat getElementById every time; very bad for performance, and the whole idea is wrong. Do it once and pass the result of the call, which will be the same for all elements.
Your alert will block everything...
I mean, useless to continue, all wrong...
—SA

G4mm4R4y 19-Nov-13 16:31pm

So 1. Use parameters, ill do that. . 2. Use the getElementById once returning the result. 3. Yes it will block everything but this ends up pausing the page in the original code. Ill upload it to this page(NOTE: This is a working version with no alerts): http://webagontrail.host56.com/ The goal is to reach the desired place and display alerts when you reach it or if your at a landmark.

W∴ Balboos, GHB 19-Nov-13 11:54am

A programming tip for you with conditional (particularly loops):

Unless it's essential that you find a specific value, you should use something like
if(miles >= 2000)
and not
if(miles == 2000)

Why? What if the reading between test intervals goes from 1999 to 2001?
Also, If you happen to have floating values, they may never exactly match.

This is just good coding practice for those who don't enjoy infinite loops.

G4mm4R4y 19-Nov-13 16:40pm

With the script i have it can never go above 2000 without hitting 2000 first. Good tip though.

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G4mm4R4y · Answer 1 · 2013-11-19T14:34:00

Solution 2

Found it! Shouldve posted whole code but when i debugged it like earlier suggested it revealed a variable was undefined and for some reason it stalled my whole code.

Posted 19-Nov-13 14:34pm

G4mm4R4y