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 JavaScript and the DOM (Retiring) Getting a Handle on the DOM Selecting Elements with the Same Class Name

Monroe Gollaher
Monroe Gollaher
7,301 Points
Posted by Monroe Gollaher
Monroe Gollaher
7,301 Points

Color not changing and "app.js:4 Uncaught TypeError: Cannot read property 'style' of undefined at app.js:4"

Hi, for some reason my code for changing the li items to purple is working great. But when trying to change the "error-not-purple" class to red, it won't work. And the only error the console gives me tells me to reference line 4, which I know is working.

Any help would be greatly appreciated! Link to workspace: https://w.trhou.se/4fl8mngpgr

1 Answer

Steven Parker
Steven Parker
230,274 Points
Steven Parker
Steven Parker
230,274 Points

When you construct a "for" loop to go through an iterable, the index values should go up to but not including the length of the iterable. That's because index numbers begin at 0 instead of 1.

So the conditional clauses of the "for" loops should use the "<" operator instead of "<=".