jquery plugin for showing tooltip on overflow

jquery.tooltiponoverflow.js

/**
 * DWTFYW License
 * Author: Tony Brix, http://tonybrix.info
 * 
 * jquery plugin for showing tooltip on overflow
 * 
 * USAGE:
 * 
 * $("input, select").tooltipOnOverflow();
 * 
 */
(function($) {
	'use strict';
	$.fn.tooltipOnOverflow = function() {
		$(this).on("mouseenter", function() {
			var text = $(this).text();

			if ($(this).is("input")) {
				text = $(this).val();
			} else if ($(this).is("select")) {
				text = $("option:selected", this).text();
			}

			var textWidth = text.width($(this).css("font-size"), $(this).css("font-family"), $(this).css("font-weight"));
			if (this.clientWidth < textWidth) {
				$(this).attr('title', text);
			} else {
				$(this).removeAttr("title");
			}
		});
	};
})(jQuery);

//modified from http://stackoverflow.com/questions/118241/calculate-text-width-with-javascript#5047712
String.prototype.width = function(fontSize, fontFamily, fontWeight) {
	var fs = fontSize || '12px',
			ff = fontFamily || 'Arial',
			fw = fontWeight || 'normal',
			o = $('<div>' + this + '</div>')
			  .css({'position': 'absolute', 'float': 'left', 'white-space': 'nowrap', 'visibility': 'hidden', 'font-size': fs, 'font-family': ff, 'font-weight': fw})
			  .appendTo($('body')),
			w = o.width();

	o.remove();

	return w;
}