to_debug.html

<!DOCTYPE html>
<html>
<head>
    <meta charset="UTF-8">
    <title>to_debug</title>
</head>
<body>
<label>Enter a number [1..10]:<input type="number" name="userInput"></label>
<button class="test">Test for even</button>
<div class="output"></div>
<script type="text/javascript">
    let userInput = document.querySelector('input[type="number"]');
    let output = document.querySelector('.output');
    let btnTest = document.querySelector('.test');


    btnTest.addEventListener("click", function(){
        x = userInput.vаlue*1;
        output.innerHTML = (x % 2) &&  "ODD" || "EVEN";
    },false)

</script>
</body>
</html>