I know, you're thinking JSON didn't exist back then, I must be trolling.
I'm not, and it did!
JSON is short for "JavaScript Object Notation". With rare exceptions, it's valid JavaScript already! So JSONP only needs pure JavaScript, nothing else.
However, back then it wasnt necessary to use object notation at all. As it was returning a script to run, the script could just call functions directly instead of assembling an object.
Aside from JavaScript, people also used a Java applet or Flash to do the communication (faster than JSONP) as most browsers had at least one of those installed. Java and Flash could both be called from JavaScript.
I know, you're thinking JSON didn't exist back then, I must be trolling.
I'm not, and it did!
JSON is short for "JavaScript Object Notation". With rare exceptions, it's valid JavaScript already! So JSONP only needs pure JavaScript, nothing else.
However, back then it wasnt necessary to use object notation at all. As it was returning a script to run, the script could just call functions directly instead of assembling an object.
Aside from JavaScript, people also used a Java applet or Flash to do the communication (faster than JSONP) as most browsers had at least one of those installed. Java and Flash could both be called from JavaScript.