Regular Expressions for Validations in Jquery

1. Allow alphabets only:
var regExpressions = "^([a-zA-Z]+(_[a-zA-Z]+)*)(\s([a-zA-Z]+(_[a-zA-Z]+)*))*$";

2. var validEmail = "^[-!#$%&'*+/0-9=?A-Z^_a-z{|}~](\.?[-!#$%&'*+/0-9=?A-Z^_a-z{|}~])*@[a-zA-Z](-?[a-zA-Z0-9])*(\.[a-zA-Z](-?[a-zA-Z0-9])*)+$"