check if form field empty js code example

Example 1: if input value is null do something

if(document.getElementById("question").value.length == 0)
{
    alert("empty")
}

Example 2: how to check if all inputs are not empty with javascript

const inputFeilds = document.querySelectorAll("input");

const validInputs = Array.from(inputFeilds).filter( input => input.value !== "");

console.log(validInputs) //[array with valid inputs]

Example 3: javascript form submit on button click check if required fields not empty

<input type="text" id="checkIt" required />