function isBlank(s)
{
  var len,k,flg;
  flg=true;

  if(s!=null)
  {
    len=s.length;
    for(k=0;k<len;k++)
    {
      if(s.substring(k,k+1) != " ")
        flg=false;
    }
  }

  return flg;
}

function validate_signup()
{
  var emailaddressStr1 = window.document.frmEmail.emailaddress.value;

  if(isBlank(emailaddressStr1))
  {
    alert("Please enter E-Mail Address.");
    window.document.frmEmail.emailaddress.value="";
    window.document.frmEmail.emailaddress.focus();

    return false;
  }

  var emailaddressPat=/^(.+)@(.+)$/;
  var specialChars="\\(\\)<>\\@%&,;:\\\\\\\"\\.\\[\\]";
  var validChars="\[^\\s" + specialChars + "\]";
  var quotedUser="(\"[^\"]*\")";
  var ipDomainPat=/^\[(\d{1,3})\.(\d{1,3})\.(\d{1,3})\.(\d{1,3})\]$/;
  var atom=validChars + '+';
  var word="(" + atom + "|" + quotedUser + ")";
  var userPat=new RegExp("^" + word + "(\\." + word + ")*$");
  var domainPat=new RegExp("^" + atom + "(\\." + atom +")*$");
  var matchArray=emailaddressStr1.match(emailaddressPat);

  if (matchArray==null)
  {
    alert("Please enter valid E-Mail Address.");
    window.document.frmEmail.emailaddress.value="";
    window.document.frmEmail.emailaddress.focus();

    return false;
  }

  var user=matchArray[1];
  var domain=matchArray[2];

  if (user.match(userPat)==null)
  {
    alert("Please enter valid E-Mail Address.");
    window.document.frmEmail.emailaddress.value="";
    window.document.frmEmail.emailaddress.focus();

    return false;
  }

  var IPArray=domain.match(ipDomainPat);

  if (IPArray!=null)
  {
    for (var i=1;i<=4;i++)
    {
      if (IPArray[i]>255)
      {
        alert("Please enter valid E-Mail Address.");
        window.document.frmEmail.emailaddress.value="";
        window.document.frmEmail.emailaddress.focus();

        return false;
      }
    }
  }

  var domainArray=domain.match(domainPat);

  if (domainArray==null)
  {
    alert("Please enter valid E-Mail Address.");
    window.document.frmEmail.emailaddress.value="";
    window.document.frmEmail.emailaddress.focus();

    return false;
  }

  var atomPat=new RegExp(atom,"g");
  var domArr=domain.match(atomPat);
  var len=domArr.length;

  if (domArr[domArr.length-1].length<2 || domArr[domArr.length-1].length>3)
  {
    alert("Please enter valid E-Mail Address.");
    window.document.frmEmail.emailaddress.value="";
    window.document.frmEmail.emailaddress.focus();

    return false;
  }

  if (len<2)
  {
    alert("Please enter valid E-Mail Address.");
    window.document.frmEmail.emailaddress.value="";
    window.document.frmEmail.emailaddress.focus();

    return false;
  }
}