[Web - JS] registration for a student

const showName = () => {
    let userInput = document.getElementById("inpt").value;
    fetch(`https://jsonplaceholder.typicode.com/users/${userInput}`)
    .then((res) => res.json())
    .then((data) =>{
        console.log(data.name);
    document.getElementById("details").innerHTML = data.name

    }).catch((err)=>{
        console.log(err);
    })
}

const sendData = () =>{
    const name = document.getElementById("name").value;
    const age = document.getElementById("age").value;
    const id = document.getElementById("id").value;
    fetch("/sendData",{
        method:"POST",
        headers: {
            "Content-Type": "application/json"
        },
        body:JSON.stringify({
            name,age,id
        })
    }).then( res => res.json()).then(data => {console.log(data);})
}

const removeUnder18 = () =>{
    fetch("/removeUnder18",{
        method: "DELETE",
        headers:{
            "Content-Type": "application/json"
        }
    }).then(res=>res.json()).then(data => console.log(data)).catch((err)=>{
        console.log(err);
    })
}

const sendAndAlert = () => {
    const userName = document.querySelector('#userName').value;
    const age = document.querySelector('#ageOf').value;
    fetch("/alertDetails",{
        method: "POST",
        headers:{
            "Content-Type": "application/json"
        },
        body:JSON.stringify({
            name:userName,
            age:age
        })
    }).then( res => res.json()).then(data =>{
        alert(data.message)
    })
}

let object = {name: "Etian",Price: 50}
localStorage.setItem('myUser',object)

// I would appreciate feedback and opinions
// Steam: CheezPuff
// Discord: CheezPuff#7720