JSFiddle - React, Tailwind, and code Playground

HTML

<div class="form">
        <label for="units">Units:</label>
        <input type="text" name="units" id="units" value="12" class="required digits"  />
    </div>

    <div class="form">
        <label for="from">Convert From:</label>
            <select name="from" id="from">
                <option value="degC">-Select an Option-</option>
            </select>
    </div>

    <div class="form">
        <label for="to">Convert Into:</label>
        <select name="to" id="to">
            <option value="degF">-Select an Option-</option>
        </select>
    </div>

    <div class="form">
        <label> &nbsp; </label>
        <input type="submit" name="submit" value="Convert!" />
    </div>

JavaScript

$('input[name="submit"]').click(function(){
    var c = new Convert();
    alert(c.convertThem());
})

function Convert(){

        this.from = $("#from").val();
        this.to = $("#to").val();
        this.units = $("#units").val();
    }

    Convert.prototype.convertThem = function(){

        if(this.from == "degC"){
            if(this.to == "degF"){
                return this.units * 1.8 + 32;
            }
        }
    }