How to loop HTML data production [{},{}] format to pass multiple data to the background

var allobject=[];$ ('. P_center '). each (function () {
Gets the value required by the object
var CourseID = $ (this). Data (' ID ');
var Buynum = $ (this). Data (' quantity ');
var Buyprice = $ ('. P_su '). Text ();

Save a good value to an object
var object = {
"CourseID": CourseID,
"Buynum": Buynum,
"Buyprice": Buyprice
}
To save an object in an array

Allobject.push (object);
});
Convert an array to a string of JSON type
var Allobjectjson = json.stringify (Allobject);

How to loop HTML data production [{},{}] format to pass multiple data to the background