Stop newline submitting a form?

Question

I have a slightly unusual form-related problem. My web app listens for scanner input from a barcode reader. The barcode reader presents as keyboard input in the following format:

~100.0101~\n

where \n is a newline. I use a global javascript listener with a regex - whenever the listener 'hears' input that matches the regex, I call my barcodeHandler() function.

Unfortunately, this doesn't interact well with forms: if the user is focussed on a form input when they scan, the form is submitted and posts back before the listener kicks in, because the form takes \n to mean 'submit'.

I can't change the scanner input, so is there any way I can stop the forms submitting when the \n is entered?

Obviously, I'd still like my forms to work with the Enter key, and I'd rather not change the default form behaviour if possible!

many thanks!

Answer 1

You need to capture the keypress on form controls and prevent the default action using preventDefault() or return false.

// do this for all <input> <textarea> and <select> elements on the page.
input.addEventListener("keypress", function(event){
    if (event.which == '10' || event.which == '13') {
        event.preventDefault();
    }
}, false);

or using jQuery:

$("input, textarea, select").keypress(function(event){
    if (event.which == '10' || event.which == '13') {
        event.preventDefault();
    }
});