<?php
if(!isset($searchItem)) { $searchItem = "randomstringset"; }
function callback($buffer) {

global $searchItem;
// surround search item items with highlight class
return (ereg_replace($searchItem, "<span class='highlight'>$searchItem</span>", $buffer));

}

ob_start("callback");
?>

<?php
$string = 'But i am not looking this simple one. what i am looking here is i searched a keyword (for eg php ). After searching I got some results from the database. if the result has a keyword php, then that all (php) word should be highlited. please help me';
$search_str = 'php';
function str_highlight ($string, $search_str) {
 if (trim($string) == '') {
  $return_str = 'Empty string';
  }
 elseif (trim($search_str) == '') {
  $return_str = 'Empty search string';
  }
 else {
// i put style="...." because i don't have a class="highlight" defined
  $return_str = preg_replace ("/$search_str/i",'<span class="highlight" style="background:#f00; color:#fff; font-weight:bold; padding:0 2px;">'.$search_str.'</span>',$string);
  }
 return $return_str;
 }
$new_str = str_highlight ($string, $search_str);
echo $new_str;
 
?>

function hl($c,$q){
 $q=explode(' ',str_replace(array('','\\','+','*','?','[','^',']','$','(',')','{','}','=','!','<','>','|',':','#','-','_'),'',$q));
 for($i=0;$i<sizeOf($q);$i++)
  $c=preg_replace("/($q[$i])(?![^<]*>)/i","<b>\${1}</b>",$c);
 return $c;
}

function hl($c,$q){
 $q=explode(' ',$q);
 for($i=0;$i<sizeOf($q);$i++)
  $c=preg_replace("/($q[$i])/i","<b>\${1}</b>",$c);
 return $c;
}

/*
SQL Query Stuff
*/
$it = htmlentities($query);
$it = highlight_string($it);
echo $it;