将json转为复杂url参数

//json转url参数
var parseParam = function(param, key) {
	var paramStr = "";
	if (param instanceof String || param instanceof Number || param instanceof Boolean) {
		paramStr += "&" + key + "=" + encodeURIComponent(param);
	} else {
		$.each(param, function(i) {
			var k = key == null ? i : key + (param instanceof Array ? "[" + i + "]" : "." + i);
			paramStr += '&' + parseParam(this, k);
		});
	}
	return paramStr.substr(1);
};
var obj = {
	"name": 'tom',
	"class": {
		"className": 'class1'
	},
	"classMates": [{
		"name": 'lily'
	}]
};
console.log(parseParam(obj));//name=tom&class.className=class1&classMates[0].name=lily
console.log(parseParam(obj, 'stu'));//stu.name=tom&stu.class.className=class1&stu.classMates[0].name=lily