Last week jQuery 1.9 was released. This is the last release before jQuery 2.0. It adds many new functions, one of them is the source map.By accessing http://ajax.googleapis.com/ajax/libs/jquery/1.9.0/jquery.min.js , you can scroll to the last line and you will see below line :　//@ sourceMappingURL=jquery.min.mapThis is source map, it is a separate file and it is put at the same directory as the source file. You can click here and see what it looks like. It's an very useful function, we will talk more about it here.1. Start from source code transformationJavaScript source codes now ...