/* Written by Ben Mitchell. */
function validateInt( value ) {
	/* The following pattern is used to check if the entered value is a simple
	   number. */
	var numPat = /^\d*$/;

	/* Check that the value is a number. */
	if ( isNaN( parseInt( value ) ) )
		return false;

	// Check that the number is a simple integer.
	var numCheck = value.match( numPat );
	if ( numCheck == null )
		return false;
	else
		return true;
} // validateInt(value)

/* Written by Ben Mitchell. */
function validateFloat( value ) {
	/* First check if it is a simple integer. */
	if ( validateInt( value ) )
		return true;

	/* The following pattern is used to check if the entered value is a simple
	   number. */
	var numPat = /^\d*\.\d*$/;

	/* Check that the value is a number. */
	if ( isNaN( parseFloat( value ) ) )
		return false;

	// Check that the number is a simple integer.
	var numCheck = value.match( numPat );
	if ( numCheck == null )
		return false;
	else
		return true;
} // validateFloat(value)

/* Written by Ben Mitchell. */
function validateMin( value, min ) {
	if ( ! validateFloat( value ) )
		return false;
	if ( parseFloat( value ) < min )
	  	return false;
	return true;
}

/* Written by Ben Mitchell. */
function validateMax( value, max ) {
	if ( ! validateFloat( value ) )
		return false;
	if ( parseFloat( value ) > max )
	  	return false;
	return true;
}

/* Written by Ben Mitchell. */
function validateRange( value, min, max ) {
	if ( ! validateFloat( value ) )
		return false;
	if ( parseFloat( value ) < min
	  || parseFloat( value ) > max )
	  	return false;
	return true;
}

/* Written by Ben Mitchell. */
function validateDate( value ) {
	// Make sure there are splits.
	if ( value.indexOf( "/" ) < 0 )
		return false;

	// Parse the numbers.
	date = value.split( "/" );
	if ( date.length != 3 )
        return false;
	for ( i = 0; i < 3; i++ )
        if ( date[i].indexOf( "0" ) == 0 )
            date[i] = date[i].substring( 1 );
	day = parseInt( date[0] );
	month = parseInt( date[1] );
	year = parseInt( date[2] );
	if ( isNaN( day ) || isNaN( month ) || isNaN( year ) )
		return false;
	if ( year < 50 )
		year += 2000;
	if ( year < 100 )
		year += 1900;

	// Check the date.
	check = new Date( year, month - 1, day );
	if ( day != check.getDate()
	  || month != check.getMonth() + 1
	  || year != check.getFullYear() )
	  	return false;
	else
		return true;
} // validateDate(value)

/* Written by Sandeep V. Tamhankar (stamhankar@hotmail.com) */
function validateEmail( 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 '" + user + "' 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 '" + domain + "' is invalid!" );
				return false;
			}
		}
	    return true;
	}
	
	// Domain is symbolic name
	var domainArray = domain.match( domainPat )
	if ( domainArray == null ) {
		// alert( "The domain name '" + domain + "' 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 > 4 ) {
	   // 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 ) {
	   // alert( "This address is missing a hostname!" );
	   return false;
	}
	
	// If we've gotten this far, everything's valid!
	return true;
} // validateEmail(value)