如何在每次提交注册表单时从数据库将变量传递给url

Question

I'm working on an online exam site. So when a user submits the registration form on my site, the user must be directed to 'url/accesscode'. Here, the accesscode variable must be sent to the URL from the database when the form is submitted. A new access code is to be sent for every new registration.

How can I accomplish this using javascript/PHP?

I tried to concatenate url using javascript, also tried hidden inputs on forms, but these will work for only single access code.

Method1 - Javascript

var aCode=“accesscode”
function onClick()
{
window.open("url"+aCode);
};

Method2 - HTML

<form action="URL" method="GET">
<input type="hidden" name="access_code" value="accesscode">
<?form>

Answer 1

You can use a couple of functions, like onclickor onsubmit(form function), but there's too a way to do that trough the input using onchangeor onblur, but you have to be beware about the behavior of each one.

Like:

onclick it'll be triggered when you click in the element. onblur it'll be triggered every time the focus is out of the element (usually it used in input of text type). onchange it'll be triggered every time the input is changing (when you filling it).

So following your sample of code the possibilities could be:

const element = document.getElementById('element');
const url = "something";
// using on change
element.onchange = function() {
    const form = document.getElementById("form");
    form.target.url = url;
}

// using onblur
element.onchange = function() {
    const form = document.getElementById("form");
    form.target.url = url;
}

// using on click
element.onclick = function() {
    const form = document.getElementById("form");
    form.target.url = url;
}

Now if you want to use in 'onsubmit' function you need referer the form element, like:

const form = document.getElementById("form");
const formUrl = "something";
form.onsubmit = function(event) {
   // if you want to prevent the default form behavior event.preventDefault();
   event.target.url = formUrl;
}

After that, you can follow your logic normal.