Validating email address using jscript without a regular expression

We can perform a very basic validation of email address with JavaScript by implementing the following three rules:

1.The email address must have @ character

2.The email address must have .(dot) character

3.There must be atleast 2 characters between @ and .(dot)

Can you try this,


var filter = /^([a-zA-Z0-9_\.\-])+\@(([a-zA-Z0-9\-])+\.)+([a-zA-Z0-9]{2,4})+$/;

if (!filter.test(email.value)) {
alert('Please provide a valid email address');

var checkEmail = function(value) {

var valid = true;

if (value.indexOf('@') == -1) {
valid = false;
} else {

var parts = value.split('@');
var domain = parts[1];

if (domain.indexOf('.') == -1) {

valid = false;

} else {

var domainParts = domain.split('.');
var ext = domainParts[1];

if (ext.length > 4 || ext.length < 2) {

valid = false;
}
}

}


return valid;

};

var form = document.getElementById('test');

var validate = function(event) {
event.preventDefault();
var val = document.getElementById('email').value;
var valid = checkEmail(val);

if (!valid) {

alert('Not a valid e-mail address');
} else {

alert('Valid e-mail address');

}
};

form.addEventListener('submit', validate, false);

There are many techniques of validating email address, each validation method has its own pros and cons. The above method doesn't require understanding of regular expressions

This satisfies all the rules you stated as well as not allowing @ to start the address and not allowing . to end the address. It does not account for multiple . in the address.

function testEmailAddress(emailToTest) {
// check for @
var atSymbol = emailToTest.indexOf("@");
if(atSymbol < 1) return false;

var dot = emailToTest.indexOf(".");
if(dot <= atSymbol + 2) return false;

// check that the dot is not at the end
if (dot === emailToTest.length - 1) return false;

return true;
}

[Fiddle][1]


[1]:

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``This is working...My own Creation :)[Email Validation][1]



[1]:

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<input type=”text” name=”email” id=”email” />
<input type=”button” name=”btnok” onclick=”validate()” />


Java Script Function


<script type=”text/javascript”>
function validate()
{
var str;
var t=1;
str =document.getElementById(‘email’).value;
if(document.getElementById(‘email’).value==”")
{
alert(“Empty”);

}
var res = str.split(‘@’);
if(str.split(‘@’).length!=2)
{
alert(“zero @ OR morethan one @ “);
t=0;
}
var part1=res[0];
var part2=res[1];

// part1
if(part1.length==0)
{
alert(“no content bfr @”);
t=0;
}
if(part1.split(” “).length>2)
{
alert(“Invalid:Space before @”)
t=0;
}

//chk afr @ content: part2
var dotsplt=part2.split(‘.’); //alert(“After @ :”+part2);
if(part2.split(“.”).length<2)
{
alert(“dot missing”);
t=0;
}
if(dotsplt[0].length==0 )
{
alert(“no content b/w @ and dot”);
t=0;
}
if(dotsplt[1].length<2 ||dotsplt[1].length>4)
{alert(“err aftr dot”);
t=0;
}

if(t==1)
alert(“woooooooooooooooooooowwwww…it is a valid email”);

}

</script>

<! -- This pretty much worked for me. Give it a try -->

<!-- begin snippet: js hide: false console: true babel: false -->

<!-- language: lang-js -->

function validateEmail(email) {
var at = email.indexOf("@");
var dot = email.lastIndexOf("\.");
return email.length > 0 &&
at > 0 &&
dot > at + 1 &&
dot < email.length &&
email[at + 1] !== "." &&
email.indexOf(" ") === -1 &&
email.indexOf("..") === -1;
}

function assert(a, b) {
return a == b;
}

console.log(assert(validateEmail("[email protected]"), true));
console.log(assert(validateEmail("[email protected]"), true));
console.log(assert(validateEmail("[email protected]"), true));
console.log(assert(validateEmail("[email protected]"), true));
console.log(assert(validateEmail("[email protected]"), true));
console.log(assert(validateEmail("[email protected]"), true));

console.log(assert(validateEmail("[email protected]"), false));
console.log(assert(validateEmail("[email protected]."), false));
console.log(assert(validateEmail("steve@steve"), false));
console.log(assert(validateEmail("@steve.com"), false));
console.log(assert(validateEmail("steve@"), false));
console.log(assert(validateEmail("steve"), false));
console.log(assert(validateEmail("[email protected]"), false));
console.log(assert(validateEmail("[email protected]"), false));
console.log(assert(validateEmail("[email protected]"), false));

<!-- end snippet -->

<! -- source

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-->

let ValidateEmailAddress = (email) => {
var countAt = 0;
for (let i = 0; i < email.length; i++) {
if (email[i] == '@')
countAt++;
if (!CheckAllowedString(email[i])) {
return false;
}
}
if (countAt > 1 || countAt == 0 ||
IsAllowedCharacter(email.charAt(0)) == false)
return false

var emailParts = email.split('@');
if (emailParts[0].length < 1 || emailParts[1] < 4 ||
emailParts[1].lastIndexOf(".") == -1) {
return false
}

var length = emailParts[1].length;
var lastIndex = emailParts[1].lastIndexOf(".");
if (length - lastIndex <= 2) return false;
//check for -,.,_ double accurance
for (let i = 0; i < email.length; i++) {
if (!IsAllowedCharacter(email[i]) && !IsAllowedCharacter(email[i
+ 1])) return false;
}
for (let i = lastIndex + 1; i < length; i++) {
if (!IsCharacterString(emailParts[1][i])) return false;
}
return true
}
let IsAllowedCharacter = (val) => {
if (typeof val === 'undefined') return true;
if (isCharacterNumeric(val) || IsCharacterString(val)) return true;
return false
}
let isCharacterNumeric = (character) => {
return $.isNumeric(character);
}
let IsCharacterString = (character) => {
var characterArray = ["a", "b", "c", "d", "e", "f", "g", "h", "i",
"j", "k", "l", "m",
"n", "o", "p", "q", "r", "s", "t", "u", "v", "w", "x", "y", "z"];
if (characterArray.indexOf(character.toLowerCase()) != -1) return
true;
return false
}
let CheckAllowedString = (chr) => {
if (chr == '@') {
return true
} else if (chr == '-') {
return true
} else if (chr == '.') {
return true
} else if (chr == '_') {
return true
} else if (IsAllowedCharacter(chr)) {
return true
} else {
return false
}
}