<?php
$s = "[{\"roll_no\":\"1101\",\"full_name\":\"John Smith\",\"dayspresent\":\"1\",\"totalclasses\":\"2\",\"percent_att\":\"\n\t\t\t50\t\t\t\",\"hasAttended\":\"P\",\"att_date\":\"Fri Apr 05 2013 \",\"st_class\":\"1\",\"st_section\":\"A\"},{\"roll_no\":\"1102\",\"full_name\":\"Ram Puri\",\"dayspresent\":\"4\",\"totalclasses\":\"4\",\"percent_att\":\"\n\t\t\t100\t\t\t\",\"hasAttended\":\"A\",\"att_date\":\"Fri Apr 05 2013 \",\"st_class\":\"1\",\"st_section\":\"A\"}]";
$json = str_replace(array("\t","\n"), "", $s);
$a = json_decode($json, true);
foreach($a as $item)
{
var_dump($item);
}