What is "URL-encoded" Form data?
Hello, I know form data is just data when we submit a form but can someone explain what do we mean by "URL-encoded" form data please, why "encoded" ?
I know we have 2 encoding, the URL-encoded thing and the multipart-formdata.
How does these 2 differ?
18 Replies
when you send a form with the GET method, it goes all into the url
url-encoded post is the same - except it goes in the body of the request and not in the url
by the way, that's the default and it can't be used to send files
encoding is a way to take data from one format to another in a predictable, reproduceable way. In the context of URL encoding, it's taking characters that have meanings in a URL that could break the data up (like a /) and replacing them with placeholders (%2F off the top of my head)
another way encoding is used is to take binary data and translate it into text. Usually that's done with utf-8 now, but in the past ISO-8859 was pretty popular too, and there's others too (like UTF-16)
ASCII is a form of encoding too, saying that binary 65 is an
A and 66 is a B for example
the exact details of how URL and multipart encoding differ isn't really important though. Their purpose is to take data and transfer it to a format that's safe to transmit over the chosen protocol, in such a way that it can be turned back into the original data on the other sideone VERY VERY important detail is that url encoded forms cannot send files
Yeah, it's limited to utf characters I think
yup, utf8 is the only allowed encoding for webpages
yeah I see
normally in a form, we have the multipart/form-data encytype and application/x-www-form-urlencoded (I think their is one more but let's consider only these 2). By default, our HTML form uses application/x-www-form-urlencoded.
Normally, when we send a GET request, the parameters/input values go into the url, special characters like a space is encoded using %20 I think. So the encoding type is just how to represent characters to make both client/servers understand things?
www-form-urlencoded can only encode text so that at the other end when it is being send to the server, we can parse it? On the other hand, using multipart/form-data, we can encode images etc?
pretty much
the way the request is built is very different too
but that's getting into the weeds
yeah, more than I've ever worried about it at least
all you really need to do is use
method="GET" only when you really know you need it, and all the rest is POSTexactly
by the way, you can use url parameters with a post request, regardless of the encoding
that's something people forget
Think of
x-www-form-urlencoded like a basic key/value pair. Like a JS object that can only have string keys and values, so no nested anything. Text only. No image, no video, no audio, no nothing.
name=13eck&has-coffee=true&age=42
Very simple. Very easy to parse and read.
multipart/form-data, on the other hand, is more complex as it's designed for transfering binary files. Audio, video, apps, pics, etc. Pretty much anything that's not sending raw text. While it can be used to send simple key/value pairs it's way overkill—like driving a Ferrari in bumper-to-bumper traffic.
Have a looksie here for simple examples of both: https://developer.mozilla.org/en-US/docs/Web/HTTP/Reference/Methods/POST#url-encoded_form_submissionyep noted, thanks !
oh ok, like query params can be used irrespective of the HTTP verb used, not just GET?
you can put query parameters in the
action attribute if you want to
that's what he's suggestingquery params are part of the URL. Anything that has a URL by definition can have query params
^ this
and query parameters are url-encoded
url-encoded is written like query params, but are not query paramsexactly
yep noted
thanks !