Validating email and password using javascript

Question

I know its good to use serverside validation for security, except this is just to get my head around validation.

My efforts so far have amounted to the following

function validateUser()
{
    var x=document.forms["myForm"]["email"].value;
    var y=document.forms["myForm"]["password"].value;
    var atpos=x.indexOf("@");
    var dotpos=x.lastIndexOf(".");
    var uppercase = password.match(/[A-Z]/)
    var lowercase = password.match(/[a-z]/g)
    var number = password.match(/[0-9]/g)
    if (atpos<1 || dotpos<atpos+2 || dotpos+2>=x.length)
    {
    alert("Not a valid e-mail address or password");
    return false;
    }else{ 
    alert("Valid Email Address and Password");
    return true;

    }
    }

Basically, I need an alert box to pop up when the password doesn't have at least 1 lowercase, uppercase and a number. So far my code is just throwing an error when the email is in the wrong format. What do I add to the if statement to check the password characters?

Thanks in advance,

James

Community · Accepted Answer · 2017-05-23 12:32:15Z

2

Few issues we have in your current implementation:

a. The error you're likely getting is that password is undefined.

Right now you're doing:

var y=document.forms["myForm"]["password"].value;

but you refer to it as "password" further on:

var uppercase = password.match(/[A-Z]/)
var lowercase = password.match(/[a-z]/g)

change the var y to:

var password=document.forms["myForm"]["password"].value;

b. To validate email, you should use a Regex such as:

var re = /^(([^<>()[\]\\.,;:\s@\"]+(\.[^<>()[\]\\.,;:\s@\"]+)*)|(\".+\"))@((\[[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\])|(([a-zA-Z\-0-9]+\.)+[a-zA-Z]{2,}))$/;

var isValidEmail = re.test(email);

c. To check for the password rules, you should just rely on the regular expressions you have in place already (and strip out the atpos, dotpos usage - that makes it much more complicated than it even needs to be).

Example:

var email='[email protected]';
var password='test-P1assword';
var hasUpper = password.match(/[A-Z]/)
var hasLower = password.match(/[a-z]/g)
var hasNumber = password.match(/[0-9]/g)

var re = /^(([^<>()[\]\\.,;:\s@\"]+(\.[^<>()[\]\\.,;:\s@\"]+)*)|(\".+\"))@((\[[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\])|(([a-zA-Z\-0-9]+\.)+[a-zA-Z]{2,}))$/;

var isValidEmail = re.test(email);

if (isValidEmail && hasUpper && hasLower && hasNumber) {
    alert("Valid Email Address and Password");
    return true;
} else { 
    alert("Not a valid e-mail address or password");
    return false;
}

JSFiddle example, complete with Regex to validate email AND password: http://jsfiddle.net/4hH3T/2/

The regex was taken from: Validate email address in JavaScript?

edited May 23, 2017 at 12:32

CommunityBot

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answered May 3, 2013 at 1:41

jrace

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10 Comments

Sim Over a year ago

Oh i see thanks for that, didn't pick that up, i'm still in a bit of mystery as how you incorporate the check for all the Regex characters though

jrace Over a year ago

Updated with regex implementation for you :-)

Sim Over a year ago

Hmm... i tried this for the password implementation without regex, what am I doing wrong? if (atpos<1 || dotpos<atpos+2 || dotpos+2>=x.length || password.match(uppercase) || password.match(lowercase) || password.match(number))

jrace Over a year ago

The vars you're putting in password.match() was already ran through a the match() method. Please see the following link for the correct usage: w3schools.com/jsref/jsref_match.asp NOTE: the match() method takes a regex and outputs a boolean. You're putting a boolean inside the match() method when you run through "password.match(uppercase) || password.match(lowercase) || password.match(number)"

jahroy Over a year ago

@jameskensington - Just forget about your code and use a regex. You're making this WAY too complicated.

|

Ravi Gadag · Accepted Answer · 2013-05-03 01:51:58Z

0

you can use regex to validate.

 var reg=/^(?=.*[a-z])(?=.*[A-Z])(?=.*\d)(?=.*(_|[^\w])).+$/;
 var isValid=reg.test(inputemail);

edited May 3, 2013 at 1:51

answered May 3, 2013 at 1:37

Ravi Gadag

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5 Comments

Ravi Gadag Over a year ago

rick.measham.id.au/paste/explain.pl?regex=%5E%28%3F%3D.*%5Ba-z%5D%29%28%3F%3D.*%5BA-Z%5D%29%28%3F%3D.*%5Cd%29%28%3F%3D.*%28_%7C%5B%5E%5Cw%5D%29%29.%2B%24

Sim Over a year ago

Oh i see what you mean, how to i check it vs the Strings though? password/email

plalx Over a year ago

@Ravi, The // form is always prefered over using the RegExp constructor, unless you are dealing with dynamic patterns.

Sim Over a year ago

would i do something like if (atpos<1 || dotpos<atpos+2 || dotpos+2>=x.length || password.contains(reg)?? i'm not too familiar with the syntax around this, i know theres a contains for string in java, not sure about script

jahroy Over a year ago

@jameskensington - The second line of this answer demonstrates how to use the regex. The first line defines a regex named reg. The second line calls reg.test() and passes a string as an argument. If the string matches the regex, reg.test() will return true. Here is some more reading on the RegExp.test() method.

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