parseInt（x，10）导致最大调用堆栈/太多的递归错误

Question

I have a simple JS function that updates a hidden textbox based on 2 input values.

Before I update the hidden text box, I use the the parseInt(x,10) to validate that input is numeric, if not I set the value to 0.

Why is this causing a too much recursion error?

  $(function () {
        $("#payment-form").on("submit",function (e) {

            var xDollars = $("#dollars").val();
            var xCents = $("#cents").val();
            //collect our form dollar and cents values, set to 0 if not int
            if (parseInt(xDollars, 10) == "NaN") {
                $("#dollars").val("0");
            }
            if (parseInt(xCents, 10) == "NaN") {
                $("#cents").val("00");
            }

            //join dollars and cents and submit transaction amount
            $("#TransactionAmount").val(xDollars + "." + xCents);
            $("#payment-form").submit();
            return true;
        });
    });

Answer 1

It's not parseInt() that's causing your problem, it's this:

        $("#payment-form").submit();

You're triggering the "submit" action from inside the "submit" handler.

If you just return true if validation succeeds, the form should submit normally.

Answer 2

That's because jQuery does not differentiate whether you are submitting a form via a submit event or via .submit() method. Therefore, if you use jQuery's $.submit() , it will fire a submit event manually.

Use vanilla-js instead. According to Form submission algorithm , that event won't be fired if you use .submit() :

If the submitted from submit() method flag is not set, then fire a simple event that bubbles and is cancelable named submit , at form . If the event's default action is prevented (ie if the event is canceled) then abort these steps. Otherwise, continue (effectively the default action is to perform the submission).

Therefore, this wouldn't be problematic:

document.getElementById('payment-form').submit();

But in this case you can just remove $("#payment-form").submit(); . If you don't cancel the event, the form should be submitted automatically.