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JavaScript Fundamentals · DOM · Lesson 24 of 48

Changing Content and Styles

Concept

Changing Content and Styles

Once selected, you can change an element's text with textContent and its appearance with the style property.

textContent is safer than innerHTML for plain text, since it never interprets the string as HTML — avoiding a common security pitfall when the text comes from user input.

By the end of this lesson
  • Explain the core idea behind Changing Content and Styles.
  • Predict output before running a change.
  • Test one realistic and one unusual input.
  • Use the result to make the next decision.
How to study this page
  1. 1. Read one concept.
  2. 2. Change the example.
  3. 3. Run, compare, and explain.
  4. 4. Complete the challenge below.
Syntax
ExampleRunnable
Try it Yourself »
Toggling a CSS class instead
Note: Toggling a class defined in your CSS is usually cleaner than setting inline styles one property at a time.
Self-check before continuing

Without looking at the example, describe what changes when you modify one input in Changing Content and Styles. Then reopen the editor and prove your explanation with a small test.

You are ready to continue when you can predict, test, and explain the result.

Your turn

Write code that changes a paragraph's text and makes it bold.

Need a nudge?

Ask about this lesson or your next move. The guide explains the path without taking the work away from you.

Ready for the next lesson?

Mark this lesson complete when you have finished the exercise.

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Console

Output will appear here...