If you want to avoid plugins, you can extract the relevant parts from the jQuery UI source:
/*!
* jQuery UI 1.8.16
*
* Copyright 2011, AUTHORS.txt (http://jqueryui.com/about)
* Dual licensed under the MIT or GPL Version 2 licenses.
* http://jquery.org/license
*
* http://docs.jquery.com/UI
*/
$.support.selectstart = "onselectstart" in document.createElement("div");
$.fn.disableSelection = function() {
return this.bind( ( $.support.selectstart ? "selectstart" : "mousedown" ) +
".ui-disableSelection", function( event ) {
event.preventDefault();
});
};
$("#somediv").disableSelection();