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html - Getting data from input using JavaScript

I am trying to get a value out of a <input type='num'> with JavaScript I am using the following code:

Choose a number between 1 and 5 <input type='num' name="input">

<button id="btn">Click me!</button>

<script>
    var input;

    document.getElementById('btn').onclick = function(){
    input = document.getElementById('num');
        alert(input); //To check what value input has
</script>

This should get a value but I just get a null what am I doing wrong?

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You have not defined your id. Also I guess your input type should be number.

<input type='number' name="input" id="num">
       ^^^^^^^^^^^^               ^^^^^^^^

And to alert its value you need to use

alert(input.value) //.value is used to get value of input

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