json对象转换为字符串

function obj2str(o) {
var r = [];
if (typeof o == "string") return "\"" + o.replace(/([\'\"\\])/g, "\\$1").replace(/(\n)/g, "\\n").replace(/(\r)/g, "\\r").replace(/(\t)/g, "\\t") + "\"";
if (typeof o == "undefined") return "undefined";
if (typeof o == "object") {
if (o === null) return "null";
else if (!o.sort) {
for (var i in o)
r.push(i + ":" + obj2str(o[i]))
r = "{" + r.join() + "}"
} else {
for (var i = 0; i < o.length; i++)
r.push(obj2str(o[i]))
r = "[" + r.join() + "]"
}
return r;
}
return o.toString();
}