XMLHttpRequest and POST question

brookie · February 24th, 2012, 08:07 PM

Hi,

I am looking at using XMLHttpRequest with a POST request. The example on page 709 works for a form, but what if I have what I want to POST in a JavaScript string variable already?

Essentially I am looking for an elegant way to transfer a string from browser JavaScript to a LAMP server. I have done it with code that creates a form and then posts the form but that seems rather a crude approach.

(Enjoying the book by the way.)

alanrew · May 10th, 2012, 04:10 PM

AFAIK all you need to do is construct a query string using names & values, pass it to send(), i.e.

Code:

xhr.send("arg1=value1&arg2=value2&arg3=value3");

that way, you're simulating how the form variables are passed to the server.
e.g.

Code:

xhr.send("user=john&[email protected]");

where 'user' and 'email' take the place of form field names, and 'john' and '[email protected]' their respective values.

In general, to be safe, you need to call encodeURIComponent() for each arg name and value, as in the serialize() function on pages 540 - 541

HTH

Alan