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;
}