/*****************************************************
 *
 *	Change Log
 *	----------
 *	None
 *
 *	Function Description
 *	--------------------
 *	This plugin constrains the keyboard input of
 *	the user.
 *
 *	Sub Functions
 *	-------------
 *	alphanumeric() - prevents the user from entering 
 *			 any non alphanumeric character
 *	numeric() - prevents the user from entering any
 *		    non-numeric values
 *	alpha() - prevents the user from entering any
 *		  non-alpha characters
 *
 *	Dependencies
 *	------------
 *	- JQuery
 *
 *****************************************************/
(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);