function checkEmail()
{
    var error_string = "";
    var the_email = window.document.email_form.toemail.value; 
    var from_email = window.document.email_form.fromemail.value; 
    var format=/^[^@]+@([-\w]+\.)+[A-Za-z]{2,4}$/;
if(the_email.search(format) == -1){
error_string += "The To email address is invalid.\n";
}
if(from_email.search(format) == -1){
error_string += "The From email address is invalid.\n";
}	    
    if (error_string == "")
        {
           return true;
        } else {
          error_string = "We found the following errors in your form: \n" + error_string;
          alert(error_string);
          return false;
        }
}