index.js

// Division of PaO2 and FiO2 inputs, and validation
function division(event) {
    event.preventDefault();

    let numberFormat = /^[0-9]+$/;
    let PaO2input = document.getElementById("PaO2").value;
    console.log(PaO2input);
    let FiO2input = document.getElementById("FiO2").value;
    console.log(FiO2input);
    if (PaO2input.match(numberFormat) && FiO2input>=0.21 && FiO2input<=1) {
        let result = PaO2input/FiO2input;
        console.log(result);
        document.querySelector("span").innerText = `Patient's PaO2/FiO2 ratio is: ${result}`;
    } else if (!PaO2input.match(numberFormat) && FiO2input>=0.21 && FiO2input<=1) {
        alert("PaO2 must be a number");
    } else if (PaO2input.match(numberFormat) && FiO2input=="") {
        alert("FiO2 must be a number");
    } else if (PaO2input.match(numberFormat) && FiO2input<=0.20) {
        alert("FiO2 at room air is 0.21 \nFiO2 cannot be less than 0.21");
    } else if (PaO2input.match(numberFormat) && !FiO2input.match(numberFormat)) {
        alert("FiO2 must be a number");
    } else if (PaO2input.match(numberFormat) && FiO2input>1) {
        alert("Please input FiO2 as decimal e.g. 50% = 0.5");
    } else {
        alert(`PaO2 must be a number \nFiO2 must be a number`);
    }
}

// Radio buttons to FiO2input
function deviceSelection() {
    if (np1.checked==true ||
        np2.checked==true ||
        np3.checked==true ||
        np4.checked==true ||
        np5.checked==true ||
        np6.checked==true ||
        nrm.checked==true){
        const rbs = document.querySelectorAll('input[name="device"]');
        let selectedValue;
            for (const rb of rbs) {
                if (rb.checked) {
                    selectedValue = rb.value;
                    break;
                }
            }
            console.log(selectedValue);
        document.getElementById("FiO2").value = selectedValue;
    }
}

// Mouseover & Mouseout Icon
function iconMouseOver() {
    document.getElementById('information').style.display = 'block';
}

function iconMouseOut() {
    document.getElementById('information').style.display = 'none';
}