How can i edit a text file on a server and how to receive it back in a text box.And at last how to check wether a particular word is there or not.

If you can get any of this then please let me know at

You may tell me in javascript side server language or anything else.
I will be grateful as i am only 13.

I believe it is php your wanting to use if the file is stored on the server.
There is a nice function called file_get_contents() and file_put_contents(). Below is an example of how to use them.

echo '<textarea name="text">';
echo $data;
echo '</textarea>';
if (isset($_POST) && !empty($_POST)) {

For checking word is there or not:
Here is code:

	$findme  = 'some word';
	$pos = strpos($data, $findme);
	// Note the use of ===.  Simply == would not work as expected
	// because the position of 'a' was the 0th (first) character.
	if ($pos === false) 
	   echo "The string '$findme' was not found";
	   echo "The string '$findme' was found and exists at position $pos";