Intercept a form submit in JavaScript and prevent normal submission
<form onSubmit="return captureForm()">
that should do. Make sure that your captureForm() method returns false.
<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()
You cannot attach events before the elements you attach them to has loaded
This works -
Plain JS
DEMO
Recommended to use eventListener
// Should only be triggered on first page load
console.log('ho');
window.addEventListener("load", function() {
document.getElementById('my-form').addEventListener("submit", function(e) {
e.preventDefault(); // before the code
/* do what you want with the form */
// Should be triggered on form submit
console.log('hi');
})
});<form id="my-form">
<input type="text" name="in" value="some data" />
<button type="submit">Go</button>
</form>but if you do not need more than one listener you can use onload and onsubmit
// Should only be triggered on first page load
console.log('ho');
window.onload = function() {
document.getElementById('my-form').onsubmit = function() {
/* do what you want with the form */
// Should be triggered on form submit
console.log('hi');
// You must return false to prevent the default form behavior
return false;
}
} <form id="my-form">
<input type="text" name="in" value="some data" />
<button type="submit">Go</button>
</form>jQuery
// Should only be triggered on first page load
console.log('ho');
$(function() {
$('#my-form').on("submit", function(e) {
e.preventDefault(); // cancel the actual submit
/* do what you want with the form */
// Should be triggered on form submit
console.log('hi');
});
});<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
<form id="my-form">
<input type="text" name="in" value="some data" />
<button type="submit">Go</button>
</form>