String.prototype.trim = function() {
   return this.replace( /^\s*/, '').replace( /\s*$/, '' );
}

function checkRegister(f){
	var errMsg = "";
	if (f.firstname.value.trim() == ""){
		errMsg += "Please fill in your first name\n";
	}
	if (f.lastname.value.trim() == ""){
		errMsg += "Please fill in your last name\n";
	}
	
	if (f.company_name.value.trim() == ""){
		errMsg += "Please fill in your company name\n";
	}
	
	var gender = "";
	for (var i=0; i < f.gender.length; i++)
	{
	   if (f.gender[i].checked)
	      {
	       gender = f.gender[i].value;
	      }
	}
	if (gender == "")
		errMsg += "Please indicate your sex\n";

	if (f.address1.value.trim()+f.address2.value.trim() == "")
		errMsg += "Please fill in your address\n";
		
	if (f.city.value.trim() == "")
		errMsg += "Please fill in a city\n";

	if (f.username.value.trim() == "")
		errMsg += "Please enter a username\n";
	
	if (f.password.value.trim() == ""){
		errMsg += "Please enter a password\n";
	}
	if (f.password_confirm.value.trim() == ""){
		errMsg += "Please confirm your password\n";
	}
	
	if (f.password.value.length < 5){
		errMsg += "Password is too short\n";
	}
	
	if (f.password.value.trim() != "" && f.password_confirm.value.trim() != "" && f.password.value.trim() != f.password_confirm.value.trim())
		errMsg += "Password cannot be confirmed\n";

	if (f.email.value.trim() == ""){
		errMsg += "Please enter an email\n";
	}
	
	if (f.email.value.trim() != "" && !emailCheck(f.email.value, f.email)){
		errMsg += "The email address entered is not valid.\n";
	}

	if  (errMsg != ""){
		alert(errMsg);
		return false;
	}
		
	if (!f.agree.checked){
		alert("You have to agree the Users License Agreement before you can register");
		return false;
	}
	return true;
}


function emailCheck (emailStr,emailObj) {
	/* 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)");
		emailObj.focus();
		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.")
	    emailObj.focus();
	    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!")
		        emailObj.focus();
			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.")
		emailObj.focus();
	    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.")
	   emailObj.focus();
	   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)
	   emailObj.focus();
	   return false
	}
	
	// If we've gotten this far, everything's valid!
	return true;
}


function checkBlog(f){
	if (f.code.value.trim() == ''){
		alert("Please enter a verification code");
		return false;
	}
	if (f.comment.value.trim() == ''){
		alert("Please enter a comment");
		return false;
	}
}