function imgLinkBlomst(img,mouse){
   if(document.images){
      if (mouse == 'o')
         document.images[img].src = 'gfx/punkt_blomst_glow_kasse.jpg';
      else
         document.images[img].src = 'gfx/punkt_blomst_kasse.jpg';
   }
}

function preLoad () {
   blomst = new Image();
   blomst.src = 'gfx/punkt_blomst_glow_kasse.jpg';
}

navn = false;
email = false;
by = false;

function changed(thisField) {
	if (thisField.name == "Navn")
		navn =  (thisField.value != "");
	else if (thisField.name == "Email") {
		email = Validate_Email_Address(thisField.value);
		if (!email)
			alert("Email adressen er forkert!");
	}
	else if (thisField.name == "By")
		by =  (thisField.value != "");
}

function focused(thisField) {
	if ((thisField.name == "Navn" && !navn) || (thisField.name == "By" && !by)
		|| (thisField.name == "Email" && !email) )
		thisField.value = "";
}

function validate(thisForm) {
	if (!navn) {
		alert("Navn skal udfyldes");
		thisForm.Navn.value = "";
		thisForm.Navn.focus();
	} else if (!email) {
		alert("Email skal udfyldes");
		thisForm.Email.value = "";
		thisForm.Email.focus();
	} else if (!by) {
		alert("Bynavn skal udfyldes");
		thisForm.By.value = "";
		thisForm.By.focus();
	}

	return (navn && email && by);
}


function Validate_String(string, return_invalid_chars)
         {
         valid_chars = '1234567890-_.^~abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ';
         invalid_chars = '';
         
         if(string == null || string == '')
            return(true);
         
         //For every character on the string.   
         for(index = 0; index < string.length; index++)
            {
            char = string.substr(index, 1);                        
            
            //Is it a valid character?
            if(valid_chars.indexOf(char) == -1)
              {
              //If not, is it already on the list of invalid characters?
              if(invalid_chars.indexOf(char) == -1)
                {
                //If it's not, add it.
                if(invalid_chars == '')
                   invalid_chars += char;
                else
                   invalid_chars += ', ' + char;
                }
              }
            }                     
            
         //If the string does not contain invalid characters, the function will return true.
         //If it does, it will either return false or a list of the invalid characters used
         //in the string, depending on the value of the second parameter.
         if(return_invalid_chars == true && invalid_chars != '')
           {
           last_comma = invalid_chars.lastIndexOf(',');
           
           if(last_comma != -1)
              invalid_chars = invalid_chars.substr(0, $last_comma) + 
              ' and ' + invalid_chars.substr(last_comma + 1, invalid_chars.length);
                      
           return(invalid_chars);
           }
         else
           return(invalid_chars == ''); 
         }


function Validate_Email_Address(email_address)
         {
         //Assumes that valid email addresses consist of user_name@domain.tld
         at = email_address.indexOf('@');
         dot = email_address.indexOf('.');
         
         if(at == -1 || 
            dot == -1 || 
            dot <= at + 1 ||
            dot == 0 || 
            dot == email_address.length - 1)
            return(false);
            
         user_name = email_address.substr(0, at);
         domain_name = email_address.substr(at + 1, email_address.length);                  
         
         if(Validate_String(user_name) === false || 
            Validate_String(domain_name) === false)
            return(false);                     
         
         return(true);
         }