facebook username validation regex pattern

Question

i need a regex pattern to validate if a string is a valid facebook username?

Answer 1

According to this site...

preg_match('/^[a-z\d.]{5,}$/i', $username);

Answer 2

var pattern=/[~!@#$%^&<>]/;

var name=$username;

var count=0;

if(pattern.test(name) )
{
   alert('only characters');
}

if(name.match(/[0-9]/))
{

    count++;
   if(count>5)
   alert('not exceds 5 digits');
}