Form validation
Definition and example
Form validation is the focus of this lesson. Check the value before sending and show the message next to the field. The task asks you to apply that idea in a small example: Where should an error message appear. Before you run the code, predict what should happen. Then Inspect the browser output and the value your code produces and compare it with your prediction. If the result differs, change one relevant line and run it again. Testing one change at a time makes the cause of a result easier to understand.
Run your code to see the output and the checks.
Submit your code to see results
Write your code in the middle column and press Run code.
Why this works
Checks on this task:
- The output must include “required”.
The task and step-by-step instructions are written as comments at the top of the editor. Change one relevant line, run it, and compare the result with these checks.
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Incorrect attempts before answer: 0 / 3
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0 passed of 56 tasks
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Worked answer
You have made three incorrect attempts. Review this example, close the window, and continue practising.