Auto Complete highlight the typed characters

Auto Complete highlight the typed characters

Dear All

I am using autocomplete / suggestion
It works great however
it has facility to hightligh the characters in bigining

example if a person typing ion
and in database table we have word  rationing

Word rationing is being display properly (word ion is in middle of string)

How can i highligh the selection part

in short word rationing I want to be displayed as rationing
highlinght the word typed by user

pls help

What had tried 
  1. <?php 
  2. $string = "Rationing is compulsory.....";
  3. $foo="<span class=\'scrolltableheading\'>foo</span>";
  4. echo "<br>".$foo."<br>";

  5.     $newstring = str_replace("ion", "foo", $string, $count);
  6.     print "$count changes were made.\n";
  7. print $newstring;
  10.             ?>
  11. <link href="menuxx/style/adminstyle.css" rel="stylesheet" type="text/css">
  12. <body class="scrolltableheading"></body>


1 changes were made. Ratfooing is compulsory.....

However I want only 


characters to be displayed in different font/ i.e highlighted 

Can i do this using JQUERY

Pls  Pls help