AJAX: Check if a string is JSON?

Question

My JavaScript sometimes crashes on this line:

var json = eval(\'(\' + this.responseText + \')\');

Crashes are caused when the argument of <

Answer 1

If you include the JSON parser from json.org, you can use its parse() function and just wrap it in a try/catch, like so:

try
{
   var json = JSON.parse(this.responseText);
}
catch(e)
{
   alert('invalid json');
}

Something like that would probably do what you want.