Mandatory fields missing alert is showing even after filling values

[anjanas]

document.body.addEventListener('click', function(event) {
            if (event.target.classList.contains("searchEMCIs")) {
		alert("clicked");
                if (document.contains(document.getElementById("emSearchPopup")))
                    document.getElementById("emSearchPopup").remove();
               var popupHtml = "";
popupHtml += '<div id="emSearchPopup" style="width: 100%;height: 50%;border: 1px solid #dfdfdf;bottom: 0;left: 0;right: 0;background: #fff;z-index: 2;">';
popupHtml += '</div>';
                document.querySelector("div.section-content").innerHTML += popupHtml;
            }
});

I have a client script in onLoad incident forms which adds a popup on click of a particular button (which I am adding through script).

When I am trying to add an incident record by filling all mandatory fields , click on the button which add popup html and then click on submit it says mandatory fields are missing.

This is happening in any scenario where I render extra html through client script. 

[anjanas]

Any help on this?