Javascript to read json which is starting with some extra string

I'm trying to read a json url but JSON appearing some extra string before JSON start

JSON script is like:

throw 'allowIllegalResourceCall is false.';
{  
   "name":"mkyong",
   "age":30,
   "address":{  
      "streetAddress":"88 8nd Street",
      "city":"New York"
   },
   "phoneNumber":[  
      {  
         "type":"home",
         "number":"111 111-1111"
      },
      {  
         "type":"fax",
         "number":"222 222-2222"
      }
   ]
}

I'm trying to read this JSON using this below javascript:

<script>
$(document).ready(function() {           
    $('.button').click(function(){
    var ur= "http://json_url";
    alert(ur);
    alert(JSON.stringify($.getJSON(ur)));
    });
});
</script>

Is there any way to read this types of Json using java script/jQuery or ajax.

read this in some api doc

JSON Security String

GET requests are protected by including a security string on the line before the JSON text. The string generally looks like "throw 'allowIllegalResourceCall is false.';". To strip out this string, a regular expression should be used. For example, in python one could use:

json = re.sub(r"^throw.*;\s*","",json)

so you just need to replace the string with "" and use slashes around the regExp.

alert($.getJSON(ur).replace(/^throw.*;\s*/,"");

source : https://developers.jivesoftware.com/api/v3/cloud/rest/index.html