function checkForm()
{
 f=document.form;
 if (f.email.value=='')
 {
  alert("Please enter your email address");
  return(false);
 }
 else
 {
  var str = f.email.value;
  var supported = 0;
  if (window.RegExp) {
    var tempStr = "a";
    var tempReg = new RegExp(tempStr);
    if (tempReg.test(tempStr)) supported = 1;
  }
  if (!supported) 
    return (str.indexOf(".") > 2) && (str.indexOf("@") > 0);
  var r1 = new RegExp("(@.*@)|(\\.\\.)|(@\\.)|(^\\.)");
  var r2 = new RegExp("^.+\\@(\\[?)[a-zA-Z0-9\\-\\.]+\\.([a-zA-Z]{2,3}|[0-9]{1,3})(\\]?)$");
  if ((!r1.test(str)==true)&&(r2.test(str)==false))
  {
   alert('Sorry, you must provide a real email address!');
   return(false);
  }
 }
}