The problem with nodejs and undefined variable

-i am new in java script and i have a problem using node js

here is my code

i am using this part to show an input box ,SkyColor

let ourApp = express()       
 
ourApp.use(express.json()) 
ourApp.get("/", function(req, res) {
    res.send(`
    <form action='/answer' method='POST'>
    <p>What color is the sky on a clear and sunny day?</p>
    <input name= "skyColor" autocomplete="off">
    <button>Submit Answer</button>
    </form>
    `)
})

then if i type blue and hit the button to that input box the if statement must chose to show “Congrats! You got the right answer.”


ourApp.post('/answer', function(req, res) {
    if(req.body.skyColor == "blue") {
        res.send(`
        <p>Congrats! You got the right answer.</p>
        <a href="/">Back to homepage</a>
        `)
        console.log(req.body.skyColor)
        } else  {
            res.send(`
            <p>Sorry, you got the wrong answer. Please try again</p>
            <a href="/">Back to homepage</a>
            `)
        }
  
})

ourApp.get('/answer', function(req, res) {
    res.send("Are you lost? There is nothing to see here.")
})
ourApp.listen(3000)

but unfortunately every time i enter “blue” the if dont work correctly and show the else part “Sorry, you got the wrong answer. Please try again”

Can you put console.log(req.body) at the top of you ourApp.post('/answer' callback? Are you using a bodyParser?