Untitled

<html>
    Mínimo: <input type="number" id="min">
    Máximo: <input type="number" id="max">
    <button onclick="funcaoTemperatura()">Verificar</button>
    <label id="label1"></label>

    <br>
    <br>
    Verifica temperatura: <input type="number" id="verifica">
    <button onclick="funcaoVerificacao()">Verificar</button>
    <label id="label2"></label>

    <br>
    <select onchange="funcaoCombo()" id="combo">
        <option selected disabled>Selecione uma opcao:</option>
        <option value="volvo">Volvo</option>
        <option value="saab">Saab</option>
        <option value="mercedes">Mercedes</option>
        <option value="audi">Audi</option>
    </select>
    <label id="label3"></label>

    <script>
        function funcaoTemperatura()
        {
            var min = document.getElementById("min").value;
            var max = document.getElementById("max").value;
            if(min>=max)
            {
                document.getElementById("label1").innerHTML="NOT OKAY";
            }
            else
            {
                document.getElementById("label1").innerHTML="OKAY";
            }
        }

        function funcaoVerificacao()
        {
            var min = document.getElementById("min").value;
            var max = document.getElementById("max").value;
            var intervalo = document.getElementById("verifica").value;
            if(intervalo>max || intervalo<min)
            {
                document.getElementById("label2").innerHTML="A temperatura esta no vermelho";
            }
            else
            {
                document.getElementById("label2").innerHTML="A temperatura esta no verde";
            }
        }

        function funcaoCombo()
        {
            var combo = document.getElementById("combo").value;
            document.getElementById("label3").innerHTML=combo;
        }


    </script>

</html>