How to intercept form submits reliably?

Question

I'm trying to intercept all kind of form submissions for a specifc form on a web page. It looks to be very simple with jQuery: form.submit(function(e) {…}) and it works beautifully if I click the submit button.

However there is also an onChange property on a select field which does this.form.submit() and it looks like this call circumvents my listener (in Chromium/Firefox):

<script type="text/javascript">
    function submitForm(e) {
        window.alert('submitted');
        e.preventDefault();
        return false;
    }

    $(document).ready(function() {
        $('#bar').submit(submitForm);
    });
</script>

<form id="bar">
    <select name="name" onChange="this.form.submit()">
        <option>Foo</option>
        <option>Bar</option>
    </select>
    <br/>
    <input type="submit"/>
</form>

Obviously in the code above I could just change this.form.submit() to a specific reference of my submit listener. However in my real app it's not that simple so I'm looking for way where I don't have to modify the onChange property.

If I did not do a stupid mistake but this is actually expected browser behavior, I'd be really glad if you could explain the event flow and why this leads to the symptoms described above.

Answer 1

Calling the form.submit() method does not trigger the submit event, just like e.g. setting the value of a text box does not trigger its change event. Try to trigger the submit event through jQuery instead:

<form id="bar">
    <select name="name" onChange="$('#bar').submit();">
        <option>Foo</option>
        <option>Bar</option>
    </select>
    <br/>
    <input type="submit"/>
</form>

According to the documentation, the default submit action on the form will be fired and the form will be submitted.