jQuery Alphanum

$("#my_input").alphanum();

Restricts the characters that may be entered into a text field.

$(selector).alphanum([optional] settings);

$(selector).alpha([optional] settings);

$(selector).numeric([optional] settings);

.alphanum()

Restrict the input to alphanumeric characters

$("#username").alphanum();

Override some of the default settings

$("#username").alphanum({
	allowSpace: false, // Allow the space character
	allowUpper: false  // Allow Upper Case characters
});

Available settings plus their default values

var DEFAULT_SETTINGS_ALPHANUM = {
	allow              : '',   // Allow extra characters
	disallow           : '',   // Disallow extra characters
	allowSpace         : true, // Allow the space character
	allowNumeric       : true, // Allow digits 0-9
	allowUpper         : true, // Allow upper case characters
	allowLower         : true, // Allow lower case characters
	allowCaseless      : true, // Allow characters that don't have both upper & lower variants - eg Arabic or Chinese
	allowLatin         : true, // a-z A-Z
	allowOtherCharSets : true  // eg é, Á, Arabic, Chinese etc
}

Convenience values for commonly used settings

$("#username").alphanum("upper");

is equivalent to

$("#username").alphanum({
	allowNumeric  : false,
	allowUpper    : true,
	allowLower    : false,
	allowCaseless : true
});

List of convenience values

var CONVENIENCE_SETTINGS_ALPHANUM = {
	"alpha"      : {
		allowNumeric : false
	},
	"upper"      : {
		allowNumeric  : false,
		allowUpper    : true,
		allowLower    : false,
		allowCaseless : true
	},
	"lower"      : {
		allowNumeric  : false,
		allowUpper    : false,
		allowLower    : true,
		allowCaseless : true
	}
};

.numeric()

Restrict the input to numeric characters

$("#weight").numeric();

Override some of the default settings

$("#weight").numeric({
	allowMinus   : false,
	allowThouSep : false
});

Available settings plus their default values

var DEFAULT_SETTINGS_NUM = {
	allowPlus           : false, // Allow the + sign
	allowMinus          : true,  // Allow the - sign
	allowThouSep        : true,  // Allow the thousands separator, default is the comma eg 12,000
	allowDecSep         : true,  // Allow the decimal separator, default is the fullstop eg 3.141
	allowLeadingSpaces  : false,
	maxDigits           : '',    // The max number of digits or '' for no max
	maxDecimalPlaces    : '',    // The max number of decimal places or '' for no max
	maxPreDecimalPlaces : '',    // The max number digits before the decimal point or '' for no max
	max                 : '',    // The max numeric value allowed
	min                 : ''     // The min numeric value allowed
}

Convenience values for commonly used settings

$("#age").numeric("integer");

Equivalent to
$("#age").alphanum({
	allowPlus:    false,
	allowMinus:   true,
	allowThouSep: false,
	allowDecSep:  false
});

List of convenience values

var CONVENIENCE_SETTINGS_NUMERIC = {
	"integer"         : {
		allowPlus:    false,
		allowMinus:   true,
		allowThouSep: false,
		allowDecSep:  false
	},
	"positiveInteger" : {
		allowPlus:    false,
		allowMinus:   false,
		allowThouSep: false,
		allowDecSep:  false
	}
};

.alpha()

Restrict the input to alphabetic characters

$("#first_name").alpha();

Equivalent to the convenience option

$("#first_name").alphanum("alpha");

Blacklist

jquery.alphanum works by maintaining a blacklist of non-alphanumeric characters. There is no whitelist. It is assumed that all unicode characters are permissable unless there is a specific rule that disallows them.

These are the blacklisted characters that are encodable using 7-bit ascii

var blacklist = '!@#$%^&*()+=[]\\\';,/{}|":<>?~`.- _';

These are the blacklisted unicode characters that can't be encoded using 7-bit ascii

var blacklist = 
	  "\xAC"     // ¬
	+ "\u20AC"   // €
	+ "\xA3"     // £
	;

The blacklist may be extended or reduced using the 'allow' and 'disallow' settings

$("#password").alphanumeric({
	allow :    '&,;', // Specify characters to allow
	disallow : 'xyz'  // Specify characters to disallow
});