MVC - Fix Error - JavaScript runtime error: Unable to get property 'unobtrusive' of undefined or null reference

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To fix it replace in Layout

 
    @Scripts.Render("~/bundles/jquery")
    @Scripts.Render("~/Scripts/CustomValidationF.js")
    @Scripts.Render("~/bundles/bootstrap")
    @RenderSection("scripts", required: false)
</body>
</html>

with

 
    @Scripts.Render("~/bundles/jquery")
    @Scripts.Render("~/bundles/jqueryval")
    @Scripts.Render("~/Scripts/CustomValidationF.js")
    @Scripts.Render("~/bundles/bootstrap")
    @RenderSection("scripts", required: false)
</body>
</html>