Code:
<html><head>
<script language = "Javascript">
function echeck(str) {
var at="@"
var dot="."
var lat=str.indexOf(at)
var lstr=str.length
var ldot=str.indexOf(dot)
if (str.indexOf(at)==-1)
{
alert("Invalid E-mail ID")
return false
}
if (str.indexOf(at)==-1 || str.indexOf(at)==0 || str.indexOf(at)==lstr)
{
alert("Invalid E-mail ID")
return false
}
if (str.indexOf(dot)==-1 || str.indexOf(dot)==0 || str.indexOf(dot)==lstr)
{
alert("Invalid E-mail ID")
return false
}
if (str.indexOf(at,(lat+1))!=-1)
{
alert("Invalid E-mail ID")
return false
}
if (str.substring(lat-1,lat)==dot || str.substring(lat+1,lat+2)==dot)
{
alert("Invalid E-mail ID")
return false
}
if (str.indexOf(dot,(lat+2))==-1)
{
alert("Invalid E-mail ID")
return false
}
if (str.indexOf(" ")!=-1)
{
alert("Invalid E-mail ID")
return false
}
return true
}
function ValidateForm(){
var emailID=document.frmSample.txtEmail
if ((emailID.value==null)||(emailID.value=="")){
alert("Please Enter your Email ID")
emailID.focus()
return false
}
if (echeck(emailID.value)==false){
emailID.value=""
emailID.focus()
return false
}
return true
}
</script>
</head>
<body>
<form name="frmSample" method="post" action="#" onSubmit="return ValidateForm()">
<p>Enter an Email Address :
<input type="text" name="txtEmail">
</p>
<p>
<input type="submit" name="Submit" value="Submit">
</p>
</form>
</body>
</html>