Validation Check Which Prompt As Soon As User Leave The Control?

We are developing an application where we have a Form to fill by users. Here is the scenario for some fields:Name : Does not contain numbers like 123 but it can be alpha-numeric like mynangal123 but does not contain special charactersOB : Does contain specific formats like mm.dd.yyyy or dd/mm/yyy or yyyy/mm/dd etc. doesn't contain alphabetsTAXID : Can be Numeric but not numbers like it can be "123" but not 123 also it can be T-125Now, as per requirement we have to validate or prompt the user for specific input if he/she did not enter the specific entry. Like if in name User enter 123456 then there should be a messagebox to warn "please enter a valid name"Restrictions : We have a option of Javascript but its not recommendable in most of scenario so, we need to create a custom validators or something else which will solve our problem.