window.addEventListener('load', function onWindowLoaded(){
var signs = [
'1', '2', '3', '+',
'4', '5', '6', '-',
'7', '8', '9', '/',
'0', '=', '.', 'c'
];
var calc = document.getElementById('calc');
var textArea = document.getElementById('inputVal');
const _prevValue =
signs.forEach(function(sign){
var signElement = document.createElement('div');
signElement.className = 'btn';
signElement.innerHTML = sign;
calc.appendChild(signElement);
});
document.querySelectorAll('#calc-wrap .btn').forEach(function(button){
button.addEventListener('click', onButtonClick);
});
function onButtonClick(e){
if(e.target.innerHTML === 'c'){
textArea.innerHTML = '0';
} else if (e.target.innerHTML === '='){
textArea.innerHTML = eval(textArea.innerHTML);
} else if (textArea.innerHTML === '0'){
textArea.innerHTML = e.target.innerHTML;
} else {
textArea.innerHTML += e.target.innerHTML;
}
}
});