Question

PHP funcitons are written in C and you can look at the source code if you like. For example here –
session_start source

What about with Javascript? How are functions like JSON.parse implemented? Where can I go to view the source?

Thanks!

Answer 1

JSON.parse is native. That means it’s defined in the browser, the implementation of the method is browser implementation specific.

v8 (Chrome) has a C++ method for JsonParser::ParseJson

spidermonkey (Firefox) has a C++ function for js_json_parse

JavaScriptCore (Webkit / Safari) has a C++ function for JSONProtoFuncParse

Rhino (Mozilla) has a Java method for parseValue

the Opera and IE implementations are closed source. I also think Nitro’s implementation is closed source aswell.

Note there are many other JavaScript engines.