How to set a Header field on POST a form?

From FormData documention:

XMLHttpRequest Level 2 adds support for the new FormData interface. FormData objects provide a way to easily construct a set of key/value pairs representing form fields and their values, which can then be easily sent using the XMLHttpRequest send() method.

With an XMLHttpRequest you can set the custom headers and then do the POST.

Set a cookie value on the page, and then read it back server side.

You won't be able to set a specific header, but the value will be accessible in the headers section and not the content body.

In fact a better way to do it to save a cookie on the client side. Then the cookie is automatically sent with every page header for that particular domain.

In node-js, you can set up and use cookies with cookie-parser.

an example:

res.cookie('token', "xyz....", { httpOnly: true });

Now you can access this :

app.get('/',function(req, res){
 var token = req.cookies.token
});

Note that httpOnly:true ensures that the cookie is usually not accessible manually or through javascript and only browser can access it. If you want to send some headers or security tokens with a form post, and not through ajax, in most situation this can be considered a secure way. Although make sure that the data is sent over secure protocol /ssl if you are storing some sensitive user related info which is usually the case.

It cannot be done - AFAIK.

However you may use for example jquery (although you can do it with plain javascript) to serialize the form and send (using AJAX) while adding your custom header.

Look at the jquery serialize which changes an HTML FORM into form-url-encoded values ready for POST.

UPDATE

My suggestion is to include either

• a hidden form element
• a query string parameter