document.getElementById("nxt-btn").addEventListener('click' ,function(){
    if(document.getElementById('personal-datail').checkValidity())
        {
            document.getElementById('page1').classList.remove('active');
            document.getElementById('page2').classList.add('active');
            document.getElementById('prv-btn').style.display = 'block';
           
        }
        else{
            document.getElementById('personal-detail').reportValidity();
    }

});

document.getElementById('prv-btn').addEventListener('click',function()
{
    document.getElementById('page2').classList.remove('active');
    document.getElementById('page1').classList.add('active');
    document.getElementById('prv-btn').style.display = 'none';
});