var arr;

    function RndResp(element,n)
    {
		if(!n) {n=1}
         arr = new Array();
		 var result = "";
        for(var i=0;i<element.length;i++)
        {
            if (element[i].checked)
                arr.push(element[i].value);
        }

		if(arr.length==0 || arr.length < n) return result;
        
        var ar = new Array();
        while(ar.length<n)
        {
            var isExists = false;
            var rnd = Math.floor((arr.length)*Math.random())
            for(i=0; i<ar.length;i++)
                if(ar[i] == rnd || ar.length == n) isExists = true;
            if(ar.length==0 || !isExists) ar.push(rnd);
        }
		for(var i=0;i<ar.length;i++)
		{
 			result += arr[ar[i]] + ", "
		}
        return result.substring(0,result.length-2);        
   }