How to inspect Javascript Objects

Question

How can I inspect an Object in an alert box? Normally alerting an Object just throws the nodename:

alert(document); 

But I want to get the properties and methods of the object in the alert box. How can I achieve this functionality, if possible? Or are there any other suggestions?

Particularly, I am seeking a solution for a production environment where console.log and Firebug are not available.

Answer 1

How about alert(JSON.stringify(object)) with a modern browser?

In case of TypeError: Converting circular structure to JSON, here are more options: How to serialize DOM node to JSON even if there are circular references?

The documentation: JSON.stringify() provides info on formatting or prettifying the output.

Answer 2

The for-in loops for each property in an object or array. You can use this property to get to the value as well as change it.

Note: Private properties are not available for inspection, unless you use a "spy"; basically, you override the object and write some code which does a for-in loop inside the object's context.

For in looks like:

for (var property in object) loop(); 

Some sample code:

function xinspect(o,i){     if(typeof i=='undefined')i='';     if(i.length>50)return '[MAX ITERATIONS]';     var r=[];     for(var p in o){         var t=typeof o[p];         r.push(i+'"'+p+'" ('+t+') => '+(t=='object' ? 'object:'+xinspect(o[p],i+'  ') : o[p]+''));     }     return r.join(i+'\n'); }  // example of use: alert(xinspect(document)); 

Edit: Some time ago, I wrote my own inspector, if you're interested, I'm happy to share.

Edit 2: Well, I wrote one up anyway.