What's the reason i have to use jsonp?

Question

What's the reason i have to use jsonp?

A few days ago i asked why i have no response from a rest server with jquery. The reason was that i must use JSONP. I tested that with a own server and it worked.

Now i have to convince my college's who have control of the right server that the output have to be JSONP instead of json.

Only i don't now exactly why i must use JSONP? And is this only a jquery problem or is it not possible with javascript at all?

Can anyone help me with these questions? Thanks

Answer 1

JSONP is used to get data via AJAX cross-domain. Well, not exactly, JSONP is actually a bit of a "hack".

AJAX requests only work on the same domain, but <script> tags can be included from any domain. This is what JSONP is, it's actually a Javascript file, that gets added as a <script> tag.

That's why in JSONP, it's callback({data: value}), this is a script that gets executed.