How do I make sure a form is validly submitted?

[A.W.H.]

I have a sign up form for users requiring each dropdown list, input, and image upload be filled and selected. How do I make sure each component has been filled before submitting and uploading the user's data to the database?

Thank you!

[Serhii Kulibaba]

Hello,

You can use next JS:

preif (Apperyio("inputName").val()){
alert("filled");
} else {
alert("empty");
}/pre