Show alert in add new list item and show confirm in cacel button click

Create a JS file and place the below code

function CancelEvent()
{
if (confirm(confMessage)) {
    return true;
}
else
{
    e.preventDefault();
}
}

function SaveEvent()
{
   alert(saveMessage);
}

function addHandler()
{
$("input[id$=SaveItem]").attr("onclick","SaveEvent();" + $("input[id$=SaveItem]").attr("onclick"));
$("input[id$=diidIOGoBack]").attr("onclick","CancelEvent();" + $("input[id$=diidIOGoBack]").attr("onclick"));
}
_spBodyOnLoadFunctionNames.push('addHandler');

Put this in content editor webpart
<script src="/....../js/NewFormScript.js"></script>
<script>
var confMessage="Confirm 'Ok' to Cancel or 'Cancel' to retain";
var saveMessage = "After saving the record, please start the workflow";
</script>


custom-redirect-after-creating-a-new-sharepoint-item

$(document).ready(function() {

 

    var button = $("input[id$=SaveItem]");

    // change redirection behavior

        button.removeAttr("onclick");

        button.click(function() {

            var elementName = $(this).attr("name");

            var aspForm = $("form[name=aspnetForm]");

            var oldPostbackUrl = aspForm.get(0).action;

            var currentSourceValue = GetUrlKeyValue("Source", true, oldPostbackUrl);

            var newPostbackUrl = oldPostbackUrl.replace(currentSourceValue, "MyRedirectionDestination.aspx");

 

            if (!PreSaveItem()) return false;

            WebForm_DoPostBackWithOptions(new WebForm_PostBackOptions(elementName, "", true, "", newPostbackUrl, false, true));

        });

     

});