Is there a way to pretty-print JSON in a web page using JavaScript?

Question

Seems to me that pretty-printing JSON is a simple enough task that JavaScript should be able to handle it. Has anyone ever written (or run across) a JavaScript function to do this?

Answer 1

An easy way to do this is to execute:

JSON.stringify(data, null, " ");

where data is the json object you want to print pretty.

Not every browser contains JSON though. You can include json.js by Douglas Crockford which add global JSON object if it is not supported natively by the browser.

• mm2001: JSON.stringify is not terribly pretty, even with extra spaces. I found the vkbeautify link below to be a great solution.
• Alexander Mills: this seems like a bad solution, since subsequent calls to pretty print JSON might be then bastardized

Answer 2

I use this bookmarklet code on my browsers to make the JSON paragraph readable

javascript:(function(){document.body.firstChild.innerHTML = JSON.stringify(JSON.parse(document.body.firstChild.innerHTML), null, 4);})();

Adding a bookmarklet is easy - right click on bookmarks bar - Add/New - provide a name and paste js in url / location box

As current day browsers are putting the json response in a <pre> tag inside, i use body.firstChild

• Jennifer Zouak: This is awesome, still working in 2023 (if you ignore the word 'bookmarklet') !

Answer 3

take a look at vkbeautify.js plugin

http://www.eslinstructor.net/vkbeautify/

it provides pretty print for both JSON and XML text.

written in plain javascript, small and fast.

• mm2001: I really liked this solution. It worked great with node and I see they also have a browser version.
• Birla: Disclaimer: vkbeautify.json is a wrapper to JSON.stingify

Answer 4

JavaScript data formatting/pretty printer

Answer 5

If you want this for yourself (debugging purposes) you can use Greasemonkey: http://misc.slowchop.com/misc/wiki/HumanReadableJSONGreasemonkey

If you want the output for your users: http://jsonformatter.curiousconcept.com/

Answer 6

What I ended up doing is installing the JSONView add-on for Mozilla. Not perfect, but it gets done what I needed done.

Answer 7

You can give this a try it will add in some nice CSS.

<pre style="font-family: Courier;background: #f4f4f4;border: solid 1px #e1e1e1;float: left;width: auto;">
 JSON.stringify(data, null,' ').replace('[', '').replace(']', '')
</pre>