1 // Password strength meter

     2 function passwordStrength(password,username) {

     3     var shortPass = 1, badPass = 2, goodPass = 3, strongPass = 4, symbolSize = 0, natLog, score;

     4 

     5 	//password < 4

     6     if (password.length < 4 ) { return shortPass };

     7 

     8     //password == username

     9     if (password.toLowerCase()==username.toLowerCase()) return badPass;

    10 

    11 	if (password.match(/[0-9]/)) symbolSize +=10;

    12 	if (password.match(/[a-z]/)) symbolSize +=26;

    13 	if (password.match(/[A-Z]/)) symbolSize +=26;

    14 	if (password.match(/[^a-zA-Z0-9]/)) symbolSize +=31;

    15 

    16 	natLog = Math.log( Math.pow(symbolSize,password.length) );

    17 	score = natLog / Math.LN2;

    18 	if (score < 40 )  return badPass

    19 	if (score < 56 )  return goodPass

    20     return strongPass;

    21 }