I have a question about Javascript

I need help with JavaScript enabled.
My job so that I can automatically send button to be pushed faster.
I use google chrome.

For example;
Automatically have form filling add-ons. (Autofill), but only to fill the send button will not print.
How can I do this automatically?

Button codes;
<input type=‘submit’ name=‘post_shout’ value=‘Shout’ class=‘button’ />

Google Chrome address bar: javascript: xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx what I need to write here?

Can I do it after 1-2 seconds and fill out?

Many thanks in advance.
(My English is poor)

If you know of a certain form field that starts off empty but then becomes autofilled, you can check against that every 200 milliseconds.

For example with this sample form:

<form id="identifierOfForm">
    <input type="text" name="nameOfField">
    <input type="submit" value="Do something">

setInterval(function () {
    var form = document.getElementById('identifierOfForm');
    if (form.elements.nameOfField.value > '') {
}, 200);

You need to consider though that you might get in trouble for this type of automated behaviour.