function emailvalidation(entered, alertbox){with (entered){apos=value.indexOf("@");dotpos=value.lastIndexOf(".");lastpos=value.length-1;if (apos<1 || dotpos-apos<2 || lastpos-dotpos>3 || lastpos-dotpos<2){if (alertbox) {alert(alertbox);} return false;}else {return true;}}}function formvalidation_signup(thisform){with (thisform){if (emailvalidation(sender_email,"You must enter a valid email address")==false) {sender_email.focus(); return false;};}}