Basic.html

<!DOCTYPE html>
<html>
<body>
    <div>
        <input type="text" id="newString"/>
        <button onClick="printString()">Confirm</button>
        <button onclick="printVar()">Stored</button>        
    </div>
    <div>
        <div id="newValue">Change value</div>
        <button onClick="changeValue()">change</button>
    </div>    
    <script>
        var newString = ""
        function printString(){
            newString = document.getElementById("newString").innerHTML
            console.log("clicked")
            console.log(newString)
        }

        function printVar(){
            console.log(newString)

        }

        function changeValue(){
            if(newString && newString !== null){
                document.getElementById("newValue").innerHTML = newString
            }
        }
    </script>
</body>
</html>