I am trying out Modal boxes in my project and I came upon a problem, that I am unable to close the modal box when a click is made outside of the Modal box. I tried the following code, but this closes the modal box at the same instant it is opened. I tried using setTimeout method too. Its not working. Could anyone help me out with this?

const gstModal=()=>{
    g=document.getElementsByClassName("modal-gst")[0];
    g.style.display="block";
    document.addEventListener('click', function(event) {
        var isClickInside = g.contains(event.target);
        if (!isClickInside) {
            closeGST();
        }
      });
}

function closeGST(){
    document.getElementsByClassName("modal-gst")[0].style.display="none";
}