JSOM to set or save null value to SharePoint Date and Time Column

Question

I had Column "StartDate" with "Date and Time Format" DateOnly and "Display Format" Display.

And I am using JSOM with OTB to save information to SharePoint list. When I use oListItem.set_item('StartDate',TempStartDateValue) I am getting error:

Request Failed. String was not recognized as a valid datetime

Can anyone help me to solve this?

var TempStartDateValue=document.getElementById("txtCertificationDate").value;
    var clientContext = new SP.ClientContext.get_current();
    var oList = clientContext.get_web().get_lists().getByTitle('TempSec2');
    var itemCreateInfo = new SP.ListItemCreationInformation();
    this.oListItem = oList.addItem(itemCreateInfo);
    *oListItem.set_item('StartDate',TempStartDateValue);*
    oListItem.update();

Answer 1

We can't update DateTime column with Null values. You need to validate if given value is null or not. If it's not then only update the list item.

if(TempStartDateValue!="")
{
    oListItem.set_item('StartDate',TempStartDateValue);
}

Answer 2

var TempStartDateValue=null;
if(document.getElementById("txtCertificationDate").value){
 TempStartDateValue=document.getElementById("txtCertificationDate").value;
}

var clientContext = new SP.ClientContext.get_current();
var oList = clientContext.get_web().get_lists().getByTitle('TempSec2');
var itemCreateInfo = new SP.ListItemCreationInformation();
this.oListItem = oList.addItem(itemCreateInfo);
*oListItem.set_item('StartDate',TempStartDateValue);*
oListItem.update();