function emailCheck (emailStr) {
/* The following pattern is used to check if the entered e-mail address
   fits the user@domain format.  It also is used to separate the username
   from the domain. */
var emailPat=/^(.+)@(.+)$/
/* The following string represents the pattern for matching all special
   characters.  We don't want to allow special characters in the address. 
   These characters include ( ) < > @ , ; : \ " . [ ]    */
var specialChars="\\(\\)<>@,;:\\\\\\\"\\.\\[\\]"
/* The following string represents the range of characters allowed in a 
   username or domainname.  It really states which chars aren't allowed. */
var validChars="\[^\\s" + specialChars + "\]"
/* The following pattern applies if the "user" is a quoted string (in
   which case, there are no rules about which characters are allowed
   and which aren't; anything goes).  E.g. "jiminy cricket"@disney.com
   is a legal e-mail address. */
var quotedUser="(\"[^\"]*\")"
/* The following pattern applies for domains that are IP addresses,
   rather than symbolic names.  E.g. joe@[123.124.233.4] is a legal
   e-mail address. NOTE: The square brackets are required. */
var ipDomainPat=/^\[(\d{1,3})\.(\d{1,3})\.(\d{1,3})\.(\d{1,3})\]$/
/* The following string represents an atom (basically a series of
   non-special characters.) */
var atom=validChars + '+'
/* The following string represents one word in the typical username.
   For example, in john.doe@somewhere.com, john and doe are words.
   Basically, a word is either an atom or quoted string. */
var word="(" + atom + "|" + quotedUser + ")"
// The following pattern describes the structure of the user
var userPat=new RegExp("^" + word + "(\\." + word + ")*$")
/* The following pattern describes the structure of a normal symbolic
   domain, as opposed to ipDomainPat, shown above. */
var domainPat=new RegExp("^" + atom + "(\\." + atom +")*$")


/* Finally, let's start trying to figure out if the supplied address is
   valid. */

/* Begin with the coarse pattern to simply break up user@domain into
   different pieces that are easy to analyze. */
var matchArray=emailStr.match(emailPat)
if (matchArray==null) {
  /* Too many/few @'s or something; basically, this address doesn't
     even fit the general mould of a valid e-mail address. */
	//alert("Email address seems incorrect (check @ and .'s)")
	return false
}
var user=matchArray[1]
var domain=matchArray[2]

// See if "user" is valid 
if (user.match(userPat)==null) {
    // user is not valid
    //alert("The username doesn't seem to be valid.")
    return false
}

/* if the e-mail address is at an IP address (as opposed to a symbolic
   host name) make sure the IP address is valid. */
var IPArray=domain.match(ipDomainPat)
if (IPArray!=null) {
    // this is an IP address
	  for (var i=1;i<=4;i++) {
	    if (IPArray[i]>255) {
	       // alert("Destination IP address is invalid!")
		return false
	    }
    }
    return true
}

// Domain is symbolic name
var domainArray=domain.match(domainPat)
if (domainArray==null) {
	//alert("The domain name doesn't seem to be valid.")
    return false
}

/* domain name seems valid, but now make sure that it ends in a
   three-letter word (like com, edu, gov) or a two-letter word,
   representing country (uk, nl), and that there's a hostname preceding 
   the domain or country. */

/* Now we need to break up the domain to get a count of how many atoms
   it consists of. */
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) {
   // the address must end in a two letter or three letter word.
   //alert("The address must end in a three-letter domain, or two letter country.")
   return false
}

// Make sure there's a host name preceding the domain.
if (len<2) {
   var errStr="This address is missing a hostname!"
   //alert(errStr)
   return false
}

// If we've gotten this far, everything's valid!
return true;
}
function readCookie(name) {
	var nameEQ = name + "=";
	var ca = document.cookie.split(';');
	for(var i=0;i < ca.length;i++) {
		var c = ca[i];
		while (c.charAt(0)==' ') c = c.substring(1,c.length);
		if (c.indexOf(nameEQ) == 0) return c.substring(nameEQ.length,c.length);
	}
	return null;
}
function createCookie(name,value,days) {
	if (days) {
		var date = new Date();
		date.setTime(date.getTime()+(days*24*60*60*1000));
		var expires = "; expires="+date.toGMTString();
	}
	else var expires = "";
	document.cookie = name+"="+value+expires+"; path=/";
}
function eraseCookie(name) {
	createCookie(name,"",-1);
}
function check_required(f,id){
	if(f.value==""){
		setStyleById(id,"color","red");
		return false;
	}
	else{
		setStyleById(id,"color","blue");
		return true;
	}
}
function setStyleById(i, p, v) {
	var n = document.getElementById(i);
	n.style[p] = v;
}
var codeval;
function check_form(f){
	var result1=check_required(document.getElementById("a"),"f1");
	var result2=check_required(document.getElementById("c"),"f2");
	var result4=check_required(document.getElementById("f"),"f4");
	var result6=check_required(document.getElementById("h"),"f6");
	var result7=check_required(document.getElementById("i"),"f7");
	var result8=check_required(document.getElementById("k"),"f8");
	var result9=check_required(document.getElementById("j"),"f9");
	var result10=check_code(document.getElementById("j"),"f9");
	var result11=emailCheck(f.email.value);
	if(!result11)setStyleById("f7","color","red");
	if(result1 && result2 && result4 && result6 && result7 && result8 && result9 && result10 && result11){
		setStyleById("error","display","none");
		return true;
	}else{
		setStyleById("error","display","block");
		document.getElementById("img1").src="../Popover/ccode.php?old="+codeval;
		return false;
	}
}
function check_code(f,id){
	codeval=f.value;
	var ccode=readCookie('captcha');
	if(codeval!=ccode){
		//alert("codeval is "+codeval+" ccode is "+ccode);
		setStyleById("error1","display","block");
		//document.getElementById("img1").src="../Popover/ccode.php?old="+codeval;
		return false;
	}else{
		setStyleById("error1","display","none");
		return true;
	}
	
}