const doc = {
    baseInput: document.querySelector("#baseInput"),
    heightInput: document.querySelector("#heightInput"),
    areaInput: document.querySelector("#areaInput"),
    calcButton: document.querySelector("#calcButton")
}
const state = {
    base: 0,
    height: 0,
    area: 0
}

window.addEventListener('load', () => {
    init();
})

function init() {
    doc.calcButton.addEventListener("click", () => {
        startCalc();
    })
}

function startCalc() {
    state.base = doc.baseInput.value;
    state.height = doc.heightInput.value;
    state.area = calcArea(state.base, state.height);
    doc.areaInput.value = state.area;
}

function calcArea(base, height) {
    return base * height / 2;
}