Help generating Regular Expression

[pranaysharmadelhi]

I want to generate a regular expression for password check.(ASP.Net)
But javascript is what it really is.
I would like to enforce Minimum 6 alphanumeric characters with minimum 1 numeric(0-9) and 1 character(a-z) or 1 Special Character(. or _)
So far I have been able to generate something so they enter 6 alpha numberic characters, but don't know a way to check presence of 1 numeric and 1 alpha-numeric characted(or special).

"^([A-Za-z0-9\._]){6}$"

Please help.

[xNephilimx]

I think the best way to do that is by doing three checks, it may be able to do that in one single regexp pattern, but I think it's not worth the time and effort, you can do this:

//the following string will validate, while if it only has numbers or only letters, it won't
var s = 'a.b123-ic83_87s';
 
if( s.match(/^[\w\._-]{6,}$/i) ) { //any word character, dashm dot or underscore, minimum 6 chars
   if( s.match(/([a-z]+)/i) && s.match(/([0-9]+)/i) ) { //if it contains at least a number AND a letter
      alert('ok');
   }
}