JSFiddle - React, Tailwind, and code Playground

HTML

<input type="number" id="txt" value="Hello"
        onkeydown="myFunction(event)"
        min="-100"
        max="100"
        step="0.05"
        >

JavaScript

function myFunction(e) {
	var min = -100;
	var max = 100;
  
	var txtValue = document.getElementById("txt").value;
	var pressedValue = e.key;
  
  var combined = parseFloat(txtValue, pressedValue);
    console.log(	`OLD:${txtValue}\nNEW:${pressedValue}\nCOMBINED:${combined}`);
  if (combined > max) {
  		
  		e.preventDefault();
      console.log('ohhw snapp');
  }
}