Email Validation in Javascript

In Javascript page:

/* in javascript page*/
function validateForm(){
	var x=document.forms["myForm"]["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;
  	}
}

In HTML page:

<form action="demo_form.asp" method="post" name="myForm">
    <label for="email">Email:</label>
    <input type="text" id="email" name="email">
    <input type="submit" value="Submit">
</form>