Could not retrieve json data from the given format
===

this is my json format <pre><code>

    ({"message":{"success":true,"result":[{"lead_no":"LEA13","lastname":"Developer","firstname":"PHP","company":"Dummies","email":"nandhajj@gmail.com","id":"10x132"},{"lead_no":"LEA14","lastname":"Venu","firstname":"Yatagiri","company":"Rsalesarm","email":"veve@jajs.com","id":"10x133"},{"lead_no":"LEA4","lastname":"Jones","firstname":"Barbara","company":"Vtigercrm inc","email":"barbara_jones@company.com","id":"10x35"},{"lead_no":"LEA1","lastname":"Smith","firstname":"Mary","company":"Vtiger","email":"mary_smith@company.com","id":"10x32"}]}})

i am trying to retrieve the whole json result values using the following snippet
<pre><code>

    if (xmlHttp.readyState==4)
    	{
    		alert(xmlHttp.status);
    		if(xmlHttp.status==200)
    		{
    						
    		alert("hi");
    		var jsondata=eval("("+xmlHttp.responseText+")") //retrieve result as an JavaScript object
       	    jsonOutput=jsondata.result;
       	    alert(jsonOutput);
    		
    		InitializeLeadStorage()
    		
        	}
    	}</pre></code>

my alert (hi ) is displayed but the  alert(jsonOutput); is undefined , please help me if you could  find any mistake 