(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
        }, 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);