How to validate a form before submitting it

I have a form. She has a submit button. I use razor

 @using (Html.BeginForm("Save", "Discount", FormMethod.Post, new { @id = "formForCreateDiscount"})) { } 

the onclick() event that runs before the onsubmit() event onsubmit() .

In onclick() I need to delete some data only if the form is valid ... validation follows the model using @Html.ValidationMessageFor(m => m.TypeDiscount, "", new { @class = "text-danger" }) .

Can I check it somehow ????