Intercept a form submit in JavaScript and prevent normal submission

by 
<form id="my-form">
    <input type="text" name="in" value="some data" />
    <button type="submit">Go</button>
</form>

In JS:

function processForm(e) {
    if (e.preventDefault) e.preventDefault();

    /* do what you want with the form */

    // You must return false to prevent the default form behavior
    return false;
}

var form = document.getElementById('my-form');
if (form.attachEvent) {
    form.attachEvent("submit", processForm);
} else {
    form.addEventListener("submit", processForm);
}

Edit: in my opinion, this approach is better than setting the onSubmit attribute on the form since it maintains separation of mark-up and functionality. But that’s just my two cents.

Edit2: Updated my example to include preventDefault()

Leave a Comment

tech