let tabBtn = document.querySelectorAll('.tab-btn')
let tabCont = document.querySelectorAll('.tab-cont')

for(i = 0; i < tabBtn.length; i++){
tabBtn[i].addEventListener('click', tabEvent)
function tabEvent(evt){
    for(j = 0; j <  tabBtn.length; j++){
        tabBtn[j].classList.remove('active')
        tabCont[j].style.display = "none"
    }
    evt.target.classList.add('active')
    let activeCont = evt.target.dataset.tab
    document.getElementById(activeCont).style.display = "block"
    }
}
document.getElementById('default').click()