da.js

let weightSlider = document.getElementById("myWeight");
let weightOutput = document.getElementById("inputWeight");

let heightSlider = document.getElementById("myHeight");
let heightOutput = document.getElementById("inputHeight");

weightOutput.innerHTML = weightSlider.value;
heightOutput.innerHTML = heightSlider.value;

weightSlider.oninput = function() {
    weightOutput.innerHTML = this.value;
}
heightSlider.oninput = function() {
    heightOutput.innerHTML = this.value;
}

function showValWeight(newVal) {
    weightSlider.value = newVal;
};

function showValHeight(newVal) {
    heightSlider.value = newVal;
};

weightSlider.addEventListener("input", updateValueWeight);
heightSlider.addEventListener("input", updateValueHeight);

function updateValueWeight(e) {
    weightOutput.value = e.srcElement.value;
}

function updateValueHeight(e) {
    heightOutput.value = e.srcElement.value;
}

function calculateBmi() {
    let weight = document.bmiForm.realweight.value;
    let height = (document.bmiForm.realheight.value) / 100;
    let realbmi = (weight) / Math.pow(height, 2);
    let realbmiOutput = document.getElementById("yourbmi");
    let messageOutput = document.getElementById("evaluationMessage");
    let roundedBmi = realbmi.toFixed(1);
    messageOutput.innerHTML = "";
    realbmiOutput.innerHTML = " " + roundedBmi;
    if (roundedBmi > 26) {
        messageOutput.innerHTML = "<br>Start workout";
    }
}