https://johner.com/js/emagasin/emagasin-formfunctions.js

1var testresults;
2function checkemail() {
3	var str = document.validation.epost.value
4	var filter = /^([\w-]+(?:\.[\w-]+)*)@((?:[\w-]+\.)*\w[\w-]{0,66})\.([a-z]{2,6}(?:\.[a-z]{2})?)$/i
5	if (filter.test(str))
6		testresults = true
7	else {
8		alert("Please input a valid email address!")
9		testresults = false
10	}
11	return (testresults)
12}
13
14function emailvalidation() {
15	if (document.layers || document.getElementById || document.all)
16		return checkemail()
17	else
18		return true
19}
20
21function ValidateEmail(mail) {
22	if (/^\w+([\.-]?\w+)*@\w+([\.-]?\w+)*(\.\w{2,3})+$/
23			.test(myForm.emailAddr.value)) {
24		return (true)
25	}
26	alert("You have entered an invalid email address!")
27	return (false)
28}