Thursday, April 30, 2009

Email syntax validation using javascript

We should validate the syntax of email entered in the form in the client side itself to save unnecessary server process to validate the email.

It can be done using javascript.
Consider below form.
onSubmit event of Form is calling a javascript function ValidateForm

<form name="frmSample" method="post" action="" onSubmit="return ValidateForm();">
<p>Enter an Email Address :
<input type="text" name="txtEmail">
<input type="submit" name="Submit" value="Submit">

The javascript function ValidateForm is calling another function emailcheck to validate syntax of the email id.

<script language = "Javascript">

function emailcheck(str) {

var at="@"
var dot="."
var lat=str.indexOf(at)
var lstr=str.length
var ldot=str.indexOf(dot)
if (str.indexOf(at)==-1){

return false //if @ symbol is not there

if (str.indexOf(at)==-1 || str.indexOf(at)==0 || str.indexOf(at)==lstr){

return false //if @ symbol available at starting or ending of email.

if (str.indexOf(dot)==-1 || str.indexOf(dot)==0 || str.indexOf(dot)==lstr){

return false //if "." is not available, or available at beginning or end of email.

if (str.indexOf(at,(lat+1))!=-1){

return false //if more one @ symbol available in email

if (str.substring(lat-1,lat)==dot || str.substring(lat+1,lat+2)==dot){

return false //if no letter is available between @ and "."

if (str.indexOf(dot,(lat+2))==-1){

return false

if (str.indexOf(" ")!=-1){

return false //if blank space available in email.

return true

function ValidateForm(){
var emailID=document.frmSample.txtEmail

if ((emailID.value==null)||(emailID.value=="")){
alert("Please Enter your Email ID")
return false
if (emailcheck(emailID.value)==false){
return false
return true

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1 comment:

Aravinth said...

In case to check whether the symbols like /:; are avail
how to validate the email

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