Empowering Today’s Learners to Become Tomorrow’s Leaders
When you run the example and get the dialog box that prompts you to enter your user name, try pressing the Cancel button. You should end up with a title that reads Mozilla is cool, null. This happens because—when you cancel the prompt—the value is set as null. Null is a special value in JavaScript that refers to the absence of a value.
Also, try clicking OK without entering a name. You should end up with a title that reads Mozilla is cool, for fairly obvious reasons.
To avoid these problems, you could check that the user hasn't entered a blank name.
Update your setUserName() function to this:
function setUserName() {
let myName = prompt('Please enter your name.');
if(!myName) {
setUserName();
} else {
localStorage.setItem('name', myName);
myHeading.innerHTML = 'JavaScipt is cool, so is ' + myName;
}
}
This forces a user to enter a name.
Enter your name!
