JQuery :: Prevent Ampersand From Splitting Up Data String During Ajax

I'm using ajax to store values from a form into MySQL. The form contains a text field named "title" and the method I'm using to fetch and pass on the data to the backend is shown below:
_data = "title=" + $( '#title' ).val();
$.ajax({
async: true,
type: "POST",
url: "backend.php",
dataType: "json",
data: _data,
success: function( json ) { .... }
}});

The method works fine for normal text, say "This is a sample text". However, if an ampersand is used in the title text (example: "This & That"), the post value is being truncated at the ampersand. In effect, the & in it is causing the string to be split up into two segments and the
part after the & is being treated as a variable,
i.e. instead of passing
title = This & That
What is being passed is,
title = This
That =
* as shown by Firebug