Validate an email addressTag(s): Language
It's impossible to check if an address is REALLY valid but we can check for the presence of the "@" character.
<HTML><HEAD>
<SCRIPT>
function validate_email() {
if(-1 == document.jsform.email.value.indexOf("@")) {
document.jsform.email.focus();
alert("Your email must have a '@'.");
return false;
}
if(-1 != document.jsform.email.value.indexOf(",")) {
document.jsform.email.focus();
alert("Your email must not have a ',' in it");
return false;
}
if(-1 != document.jsform.email.value.indexOf("#")) {
document.jsform.email.focus();
alert("Your email must not have an '#' in it." );
return false;
}
if(-1 != document.jsform.email.value.indexOf("!")) {
document.jsform.email.focus();
alert("Your email must not have a '!' in it." );
return false;
}
if(-1 != document.jsform.email.value.indexOf(" ")) {
document.jsform.email.focus();
alert("Your email must not have a space in it." );
return false;
}
if(document.jsform.email.value.length ==
(document.jsform.email.value.indexOf("@")+1) ) {
document.jsform.email.focus();
alert("Your email must have a domain name after the '@'.");
return false;
}
if(document.jsform.email.value.length == 0) {
document.jsform.email.focus();
alert("Please enter your email.");
return false;
}
return true;
}
</SCRIPT><BODY>
Press ENTER to validate this email address
<FORM NAME="jsform"
ONSUBMIT="return validate_email()">
<INPUT NAME="email"
TYPE="text"
SIZE="50">
</FORM></BODY></HTML>
Alternate way using regular expression:
<script>
function checkemail(str){
var filter=/^[a-zA-Z0-9._-]+@[a-zA-Z0-9.-]+\.[a-zA-Z]{2,4}$/
if ( !filter.test(str)) {
alert ("bad");
return false;
}
else {
alert ("ok");
return true;
}
}
</script>
Press ENTER to validate this email address
<FORM NAME="jsform"
ONSUBMIT="return checkemail(document.jsform.email.value)">
<INPUT NAME="email"
TYPE="text"
SIZE="50">
</FORM>