Regular expression for first and last name

Question

For website validation purposes, I need first name and last name validation.

For the first name, it should only contain letters, can be several words with spaces, an

Answer 1

var name = document.getElementById('login_name').value; 
if ( name.length < 4  && name.length > 30 )
{
    alert ( 'Name length is mismatch ' ) ;
} 


var pattern = new RegExp("^[a-z\.0-9 ]+$");
var return_value = var pattern.exec(name);
if ( return_value == null )
{
    alert ( "Please give valid Name");
    return false; 
}