Using Comparison Operators correctly

Question

I am new to HTML and have used Eclipse for Java before. Below I am trying to have the user input a number (0-5) and have the computer try and guess it.

I have looked this over and it seems sound, the only thing that I have never done is put an item equal to another item at the end of the loop.

Also first time using not statements ( is it !== or !=? ) in HTML/JavaScript .

HTML

<p>How many fingers am I holding up?</p>
<input id="fingers"></input>
<div>
    <button id="button">Input fingers</button>
</div>

JavaScript

var i = 0;
var cg = 0;

document.getElementById("button").onclick = function() {
    while (i !== fingers) {
        cg = Math.random();
        cg = cg * 6;
        cg = Math.floor(cg);

        if (document.getElementById("cg").value !== fingers) {
            alert("Wrong we found " + cg);
            i = cg;
        } else {
            alert("The number of fingers is " + cg);
            i = cg;
        }
    }
}

I am independently learning this for future use, I hope you can help! Thanks.

Answer 1

You don't have html element with id cg , so this line fails document.getElementById("cg").value . However you have fingers as an html textbox.

Also first time using not statements (is it !== or !=?) in HTML/JavaScript.

In js, both are valid but they differ in functionality, != has an overhead of conversion. For eg

5 != '4' // true
5 != '5' // false

5 !== '4' // true
5 !== '5' // true

5 !== 5 // false
5 !== 4 // true

I tried to rectify your code and I ended up with this, hope it helps:

<script type="text/javascript">

var cg;
var fingers = document.getElementById("fingers");

document.getElementById("button").onclick=function() {
  cg = Math.floor(Math.random()  * 6);
  if (fingers.value != cg) {
    alert ("Wrong, it was: " + cg);
  }
  else {
    alert ("Right !!");
  }
};
</script>

Answer 2

<script type="text/javascript">
    var i = 0;
    var cg = 0;

    document.getElementById("button").onclick = function() {
        while (i !== fingers.value) {
            cg = Math.random();
            cg = cg * 6;
            cg = Math.floor(cg);

            if (parseInt(cg) !== parseInt(fingers.value)) {
                alert("Wrong we found " + cg);
                i = cg;
            } else {
                alert("The number of fingers is " + cg);
                break;
            }
        }
    }
</script>

Answer 3

Check your IDs! Your JS is trying to find an element that is identified as 'cg', but the only IDs I see are 'button' and 'fingers'.