<html> <head> <script type="text/javascript" src="https://cdnjs.cloudflare.com/ajax/libs/yamljs/0.3.0/yaml.min.js"></script> </head> <body> Hello! <br /> <pre id="yaml"></pre> <script> document.getElementById("yaml").innerHTML = YAML.stringify(JSON.parse("[1,2,3,{\"a\":3}]")); </script> </body> </html>