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JavaScript JavaScript and the DOM (Retiring) Responding to User Interaction Listening for Events with addEventListener()

Brian Patterson
Brian Patterson
19,588 Points
Posted by Brian Patterson
Brian Patterson
19,588 Points

Why is this not working

In the console, it is saying that toUppercase is not a function. Not sure what I have done wrong. I think I have typed this word for word.

for (let i = 0; i < listItems.length; i+=1) {
    listItems[i].addEventListener('mouseover', () => {
    listItems[i].textContent = listItems[i].textContent.toUppercase();
    });

    listItems[i].addEventListener('mouseout', () => {
      listItems[i].textContent = listItems[i].textContent.toLowercase();
    });
  }

1 Answer

Jennifer Nordell
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STAFF
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Jennifer Nordell
Treehouse Teacher
Jennifer Nordell
.a{fill-rule:evenodd;}techdegree
Jennifer Nordell
Treehouse Teacher

Hi there! You're doing fantastic, but remember, just about everything in programming is case-sensitive. There is no toUppercase() nor toLowercase() function. There is, however, a toUpperCase() function and a toLowerCase() function. Note the capitalization of the "C" in both of these.

Hope this helps! :sparkles: