function checkFields(form) {
    if ( isBlank(form.first.value) ) {
      window.alert("Please enter your name.");
      form.first.focus();
      return false;
    }
				
    else if ( !checkEmailAddress(form.fromemail.value) ) {
      form.fromemail.value = "";
      window.alert("Please enter a valid email address.");
      form.fromemail.focus();
      return false;
    }
				
    else if ( isBlank(form.tofirst.value)) {
      window.alert("Please enter your friend\'\s name.");
      form.tofirst.focus();
      return false;
    }
				
				
    else if ( !checkEmailAddress(form.toemail.value) ) {
      form.toemail.value = "";
      window.alert("Please enter a valid email address for your friend.");
      form.toemail.focus();
      return false;
    }

  function isBlank(s) {
    for( var i=0;i<s.length;i++ ) {
      var c = s.charAt(i);
      if( (c != ' ') && (c != '\n') && (c != '\t') )
        return false;
    }
    return true;
  }
  
  function checkEmailAddress( emailStr ) {
    var emailPat=/^(.+)@(.+)$/
    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=emailStr.match(emailPat)

    if (matchArray==null) {
      return false
    }

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

    if (user.match(userPat)==null) {
      return false
    }

    var IPArray=domain.match(ipDomainPat)
    if (IPArray!=null) {
        for (var i=1;i<=4;i++) {
        if (IPArray[i]>255) {
        return false
        }
      }
      return true
    }

    var domainArray=domain.match(domainPat)
    if (domainArray==null) {
      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) {
       return false
    }

    // Make sure there's a host name preceding the domain.
    if (len<2) {
       return false
    }

    return true;
  }

  function unChecked(s){
    var isSelected = false;
    for (var i = 0; i < s.length; i++)
    {
      if (s[i].checked)
      {
        isSelected = true;
      }
    }
    if(isSelected)
    {
      return true;
    }
    return false;
  }
}

function textCounter(field, maxlimit) {
  if (field.value.lenght < maxlimit) {
    null;  
  } else if (field.value.length > maxlimit) {
    window.alert("You may only enter up to 400 characters for your message. Your message has been truncated to 400 characters to meet this criteria.");
    field.value = field.value.substring(0, maxlimit);
  }
}