I want to validate password :

• contain at least 1 number
• contain at least 1 capital letter (uppercase)
• contain at least 1 normal letter (lowercase)

I used this code

function validate()
{   
    var a=document.getElementById("pass").value
    var b=0
    var c=0
    var d=0;
    for(i=0;i<a.length;i++)
    {
        if(a[i]==a[i].toUpperCase())
            b++;
        if(a[i]==a[i].toLowerCase())
            c++;
        if(!isNaN(a[i]))
            d++;
    }
    if(a=="")
    {
        alert("Password must be filled")
    }
    else if(a)
    {
        alert("Total capital letter "+b)
        alert("Total normal letter "+c)
        alert("Total number"+d)
    }   
}

One thing that make me confuse is why if I input a number, it also count as uppercase letter???

I want to validate password :

• contain at least 1 number
• contain at least 1 capital letter (uppercase)
• contain at least 1 normal letter (lowercase)

I used this code

function validate()
{   
    var a=document.getElementById("pass").value
    var b=0
    var c=0
    var d=0;
    for(i=0;i<a.length;i++)
    {
        if(a[i]==a[i].toUpperCase())
            b++;
        if(a[i]==a[i].toLowerCase())
            c++;
        if(!isNaN(a[i]))
            d++;
    }
    if(a=="")
    {
        alert("Password must be filled")
    }
    else if(a)
    {
        alert("Total capital letter "+b)
        alert("Total normal letter "+c)
        alert("Total number"+d)
    }   
}

One thing that make me confuse is why if I input a number, it also count as uppercase letter???

• javascript
• validation

4 Answers 4

Regular expressions are more suitable for this. Consider:

var containsDigits = /[0-9]/.test(password)
var containsUpper = /[A-Z]/.test(password)
var containsLower = /[a-z]/.test(password)

if (containsDigits && containsUpper && containsLower)
....ok

A more pact but less patible option is to use a boolean aggregate over an array of regexes:

var rules = [/[0-9]/, /[A-Z]/, /[a-z]/]
var passwordOk = rules.every(function(r) { return r.test(password) });

Docs: test, every

"1".toUpperCase == "1" ! What do you say about that :) You could do your checking like this:

for(i=0;i<a.length;i++)
    {
        if('A' <= a[i] && a[i] <= 'Z') // check if you have an uppercase
            b++;
        if('a' <= a[i] && a[i] <= 'z') // check if you have a lowercase
            c++;
        if('0' <= a[i] && a[i] <= '9') // check if you have a numeric
            d++;
    }

Now if b, c, or d equals 0, there is a problem.

toUpperCase() and toLowerCase() will still return the character if it's not able to be converted, so your tests will succeed for numbers.

Instead, you should check first that isNaN(a[i]) is true before testing using toLowerCase/toUpperCase.

The very short way could be:

var pwd = document.getElementById("pass").value,
    valid = Number(/\d/.test('1abcD'))+
            Number(/[a-z]/.test('1abcD'))+
            Number(/[A-Z]/.test('1abcD')) === 3;