Can I convert a string to float in HTML with Javascript and get Square Root?

Question

I'm quite new to JavaScript and I have a problem. I want a user to input a number into a text input box and when they click a button, an alert box appears telling the Square Root of their number. The problem is, when the box appears, the message says 'NaN'? Can somebody help?

function convert(){
  var userInput = Number(document.getElementById("sqrinput"));
  alert(Math.sqrt(parseFloat(userInput)));
}

Thanks!

`document.getElementById("sqrinput")` returns the DOM element itself, not the value of the input field. — Felix Kling, Jan 24 '19 at 19:48
Possible duplicate of [How do I get the value of text input field using JavaScript?](https://stackoverflow.com/q/11563638/218196) — Felix Kling, Jan 24 '19 at 19:48

score 0 · Accepted Answer · answered Jan 24 '19 at 19:53

You want the value of the #sqrinput element:

function convert() {
  var userInput = Number(document.getElementById("sqrinput").value);
  alert(Math.sqrt(parseFloat(userInput)));
}
document.getElementById("btn").addEventListener("click", convert);

<input id="sqrinput" />
<button id="btn">Square</button>

Can I convert a string to float in HTML with Javascript and get Square Root?

1 Answers1