Counting Characters by type.

counting.js

  var pass = document.basic.password.value;
  var chars = pass.length;
  var l_let = pass.match(/[a-z]/g).length;
  var u_let = pass.match(/[A-Z]/g).length;
  var num = pass.match(/\d/g).length;
  alert(
    "# Chars:   "+chars+"\n"+
    "# Lower:   "+l_let+"\n"+
    "# Upper:   "+u_let+"\n"+
    "# Numbers: "+num
  );
  
  //Source: http://forums.phpfreaks.com/topic/97635-count-number-of-lowercaseuppercasenumbers-in-a-string/