var foo = { bar : 1 };
When you do:
console.log(foo.toString())
It will no longer display the object, but display the string representation of the object, which is [object Object] as with most objects. The same will happen if you cast it implicitly:
console.log('This is my object: ' + foo); // This is my object [object Object]
To display the object and not its string representation you need to pass the object as a parameter to console.log:
console.log(foo); // { bar : 1 }
console.log('This is my object', foo); // This is my object { bar : 1 }
In your example if you want to display the jQuery wrapper object aroud the HTML Element that fired the dblclick event, you can do this:
$(document).on("dblclick", "td.edit", function(){ console.log($(this)); });
If you want just the HTML Element, you can do this:
$(document).on("dblclick", "td.edit", function(){ console.log(this); });