E-Mail validation in Acrobat Form

Hi,

iam trying to validate a field as an email and got this script. It's working so far, but it dosn't edelte the field after the "is not valid" message. Can anyone help me?

var email = /^[a-zA-Z0-9._-]+@([a-zA-Z0-9.-]+\.)+[a-zA-Z0-9.-]{2,4}$/; if (event.value!=""){if (!email.test(event.value)){event.rc = false;app.alert("\"" + event.value + "\" is not a valid email address.");};};