Task 2: Adding Validation

Adding Alerts

Now, let’s add validation to notify the user if they forgot to enter a value for any one of the fields.

This process is going to look similar to the validation section in the chapter on forms. Add an alert to notify the user that all fields are required.

You also want to make sure that the user entered valid info for each of the fields. Valid information for the fields means that the user submits a value that is easily converted to the correct data type for our fellow engineers. The pilot and co-pilot names should be strings and the fuel level and cargo mass should be numbers. To do this, complete the helper function in your scriptHelper.js called validateInput(). validateInput() should take in a string as a parameter and return "Empty", "Not a Number", or "Is a Number" as appropriate. In scriptHelper.js, you will use validateInput() to complete the formSubmission() function. formSubmission() will take in a document parameter and strings representing the pilot, co-pilot, fuel level, and cargo mass. Using the values in those strings and the document parameter for your HTML document, update the shuttle requirements as described below. Make sure to call your formSubmission() function at the appropriate time in your script.js file!


If you want to check if something is NaN, you cannot use == or ===. Instead, JavaScript has a built-in method called isNaN(value) that returns true if value is NaN and false if value is not NaN.

Updating Shuttle Requirements

The list of shuttle requirements, the div with the id faultyItems, should be updated if something is not ready for launch. Using template literals, update the li elements pilotStatus and copilotStatus to include the pilot’s name and the co-pilot’s name.

If the user submits a fuel level that is too low (less than 10,000 liters), change faultyItems to visible with an updated fuel status stating that there is not enough fuel for the journey. The text of the h2 element, launchStatus, should also change to “Shuttle not ready for launch” and the color should change to red.

If the user submits a cargo mass that is too large (more than 10,000 kilograms), change the list to visible with an updated cargo status stating that there is too much mass for the shuttle to take off. The text of launchStatus should also change to “Shuttle not ready for launch” and the color should change to red.

If the shuttle is ready to launch, change the text of launchStatus to green and display “Shuttle is ready for launch”.


The autograder will check if your CSS is set to just red or green. While we normally encourage you to be creative, in this case, we ask that you only use "red" or "green" for the autograder.