POST request in Nintex Forms javascript to save data to sharepoint lists

Thanks for replying.. My javascript looks like below:

function save() {

NWF$('.saveButton').click();

var Client = NWF$(".nsClient option:selected").text();
var CaseType = NWF$(".nsCaseType option:selected").text();
var FundDate = NWF$(".nsDate input").val();
var Plan = NWF$(".nsPlan option:selected").text();

var hostweburl = decodeURIComponent(getQueryStringParameter("SPHostUrl"));
var addNewItemUrl = hostweburl + "/_api/Web/Lists/GetByTitle('Onboarding')/Items";

alert(hostweburl);
alert(addNewItemUrl);

var data = {
__metadata: {
'type': 'SP.Data.SpListItem'
},
Client: Client,
Case_Type: CaseType,
Estimated_Funding_Date: FundDate,
Plan: Plan

};
alert("Before item addition");
addNewItem(addNewItemUrl, data, hostweburl);
}

function addNewItem(addNewItemUrl, data, hostweburl) {
var executor = new SP.RequestExecutor(hostweburl);
executor.executeAsync({
url: addNewItemUrl,
type: "POST",
headers: {
"accept": "application/json;odata=verbose"
},
data: JSON.stringify(data),
success: function(data) {
console.log("Item Created");
console.log(data);
},
error: function(error) {
console.log(JSON.stringify(error));
}
});

}