JSFiddle - React, Tailwind, and code Playground

HTML

<p>Your weight:<input type="number" id="value1" /></p>

<p>Your height (in inches):<input type="number" id="value2" /></p>

<button onclick="calc()">Calculate</button>

<script>
   function calc() {
    var data1 = document.getElementById("value1").value;
    var data2 = document.getElementById("value2").value;
    var weight = (data1 * 703);
    var height = (weight) / (data2 * data2);
    alert("Your BMI is " + height);
} 
</script>