Client-Side Validation

Note: In this unit's Application, you will complete two small projects. Web developers often use JavaScript to validate user inputs or perform calculations before submitting the information to the server. Common validations include checking that the user has entered every required value, that values have a correct format, and that the values are in an acceptable range. In this Application, use JavaScript to add interaction and validation to your "catalog" web page. First, add an input text box for the user's age. Next, create functions to validate the name, age, and item selection in a JavaScript file. Specifically, check for the following: The user has entered a name Age is a number between 18 and 110 An item is selected Ensure that a handler returns true if the input is acceptable and false otherwise. Add an onSubmit attribute to the form tag so that a validation failure prevents the form submission. How can you tell whether the form submitted successfully or not? Modify your JavaScript so that it displays an appropriate confirmation or error message as an alert.