(function($) {

  $.fn.alphanumeric = function(p) {

    p = $.extend({
      ichars: "!@#$%^&*()+=[]\\\';,/{}|\":<>?~`.- ",
      nchars: "",
      allow: ""
    }, p);

    return this.each
			(
				function() {

				  if (p.nocaps) p.nchars += "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
				  if (p.allcaps) p.nchars += "abcdefghijklmnopqrstuvwxyz";

				  s = p.allow.split('');
				  for (i = 0; i < s.length; i++) if (p.ichars.indexOf(s[i]) != -1) s[i] = "\\" + s[i];
				  p.allow = s.join('|');

				  var reg = new RegExp(p.allow, 'gi');
				  var ch = p.ichars + p.nchars;
				  ch = ch.replace(reg, '');

				  $(this).keypress
						(
							function(e) {

							  if (!e.charCode) k = String.fromCharCode(e.which);
							  else k = String.fromCharCode(e.charCode);

							  if (ch.indexOf(k) != -1) e.preventDefault();
							  if (e.ctrlKey && k == 'v') e.preventDefault();

							}

						);

				  $(this).bind('contextmenu', function() { return false });

				}
			);

  };

  $.fn.numeric = function(p) {

    var az = "abcdefghijklmnopqrstuvwxyz";
    az += az.toUpperCase();

    p = $.extend({
      nchars: az,
      allow: ",."
    }, p);

    return this.each(function() {
      $(this).alphanumeric(p);
    }
		);

  };

  $.fn.alpha = function(p) {

    var nm = "1234567890";

    p = $.extend({
      nchars: nm
    }, p);

    return this.each(function() {
      $(this).alphanumeric(p);
    }
		);

  };

})(jQuery);