echo the php code with the help of jquery and css

hello friends,
it's so cool to having work experience with multiple things. In this example i want to share tell a simple way to add css, jquery with php.
here is my example.

$string = "Hello world!";

now we have to give some css in our example

.p_style{
 color:#ff6600;
 background:#ccc;
 padding:5px;
 }

now lets work

on some jquery who's gives a nice look to our output

$(document).ready(function(){
   $('#msg').addClass('p_style');
 });

and now the final output with our html tags after the body start and before the body end

echo "
" . $string . "
";

and you will get a nice and cool output