Welcome to the Treehouse Community

Want to collaborate on code errors? Have bugs you need feedback on? Looking for an extra set of eyes on your latest project? Get support with fellow developers, designers, and programmers of all backgrounds and skill levels here with the Treehouse Community! While you're at it, check out some resources Treehouse students have shared here.

Looking to learn something new?

Treehouse offers a seven day free trial for new students. Get access to thousands of hours of content and join thousands of Treehouse students and alumni in the community today.

Start your free trial

JavaScript

Posted by Federico Reggiardo
Federico Reggiardo
3,316 Points

Having problem with a little flashing metronome project I'm working on.

I'm using .setInterval to flash the screen between two colors and HTML buttons to increase or decrease the flash rate. The problem lies in that my variables for the increased or decreased flash rate functions call the original flash rate function and everything gets convoluted. I've tried a bunch of ways to address this and I can't get it right; too new to JS. Any thoughts?

As a secondary question if you have the time.... What would be a better approach for adjusting flash rate? Form? Drop down menu? Etc.

Here is the link to my codepen http://codepen.io/Fedreg/pen/aNJojy

Thanks for any help!!

Federico Reggiardo
Federico Reggiardo
3,316 Points

New url http://codepen.io/Fedreg/pen/xVqwjQ

2 Answers

akak
akak
29,446 Points
akak
akak
29,446 Points

Hi, The problem is that you don't stop any interval, just add one after another. You need to assign interval to a variable and then you can clear interval.

var x = 500;
var flashStep = 1;
var myInterval;

function flash() {
  if (flashStep == 1) {
    document.bgColor = "#51cfff";
    flashStep = 2;
  } else {
    document.bgColor = "#333";
    flashStep = 1;
  }
}

function faster() {
  window.clearInterval(myInterval);
  myInterval = window.setInterval(flash, x -= 50);
}

function slower() {
  window.clearInterval(myInterval);
  myInterval = window.setInterval(flash, x += 50);
}

myInterval = window.setInterval(flash, x);
Federico Reggiardo
Federico Reggiardo
3,316 Points
Federico Reggiardo
Federico Reggiardo
3,316 Points

Thanks akak!! I tried a solution like that but couldn't quite get it right; was over complicating it. Thanks again!