E-mail Validation

The function below checks if the content has the general syntax of an email.
This means that the input data must contain an @ sign and at least one dot (.). Also, the @ must not be the first character of the email address, and the last dot must be present after the @ sign, and minimum 2 characters before the end:

<title>JavaScript Validations</title>
function validateForm()
var x=document.forms["Form1"]["email"].value;
var atpos=x.indexOf("@");
var dotpos=x.lastIndexOf(".");
if (atpos<1 || dotpos<atpos+2 || dotpos+2>=x.length)
  alert("Not a valid e-mail address");
  return false;
<form name="Form1" action="second.php" onsubmit="return validateForm()" 
  <input type="text" name="email">
  <input type="submit" value="Submit">