1 // Password strength meter

     2 function passwordStrength(password1, username, password2) {

     3 	var shortPass = 1, badPass = 2, goodPass = 3, strongPass = 4, mismatch = 5, symbolSize = 0, natLog, score;

     4 

     5 	// password 1 != password 2

     6 	if ( (password1 != password2) && password2.length > 0)

     7 		return mismatch

     8 

     9 	//password < 4

    10 	if ( password1.length < 4 )

    11 		return shortPass

    12 

    13 	//password1 == username

    14 	if ( password1.toLowerCase() == username.toLowerCase() )

    15 		return badPass;

    16 

    17 	if ( password1.match(/[0-9]/) )

    18 		symbolSize +=10;

    19 	if ( password1.match(/[a-z]/) )

    20 		symbolSize +=26;

    21 	if ( password1.match(/[A-Z]/) )

    22 		symbolSize +=26;

    23 	if ( password1.match(/[^a-zA-Z0-9]/) )

    24 		symbolSize +=31;

    25 

    26 	natLog = Math.log( Math.pow(symbolSize, password1.length) );

    27 	score = natLog / Math.LN2;

    28 

    29 	if (score < 40 )

    30 		return badPass

    31 

    32 	if (score < 56 )

    33 		return goodPass

    34 

    35     return strongPass;

    36 }