// FormChek.js
//
// SUMMARY
//
// This is a set of JavaScript functions for validating input on 
// an HTML form.
//
//
// Many of the below functions take an optional parameter eok (for "emptyOK")
// which determines whether the empty string will return true or false.
// Default behavior is controlled by global variable defaultEmptyOK.
//
// BASIC DATA VALIDATION FUNCTIONS:
//
// isDigit (c)                         Check whether character c is a digit 
// isFloat (s [,eok])                  True if string s is an unsigned floating point (real) number. (Integers also OK.)
//
// Performance hint: when you deploy this file on your website, strip out the
// comment lines from the source code as well as any of the functions which
// you don't need.  This will give you a smaller .js file and achieve faster
// downloads.
//
// 18 Feb 97 created Eric Krock
//
// (c) 1997 Netscape Communications Corporation



// VARIABLE DECLARATIONS


// decimal point character differs by language and culture
var decimalPointDelimiter = ".";

// Global variable defaultEmptyOK defines default return value 
// for many functions when they are passed the empty string. 
// By default, they will return defaultEmptyOK.
//
// defaultEmptyOK is false, which means that by default, 
// these functions will do "strict" validation.  Function
// isInteger, for example, will only return true if it is
// passed a string containing an integer; if it is passed
// the empty string, it will return false.
//
// You can change this default behavior globally (for all 
// functions which use defaultEmptyOK) by changing the value
// of defaultEmptyOK.
//
// Most of these functions have an optional argument emptyOK
// which allows you to override the default behavior for 
// the duration of a function call.
//
// This functionality is useful because it is possible to
// say "if the user puts anything in this field, it must
// be an integer (or a phone number, or a string, etc.), 
// but it's OK to leave the field empty too."
// This is the case for fields which are optional but which
// must have a certain kind of content if filled in.

var defaultEmptyOK = false;

// Check whether string s is empty.

function isEmpty(s)
{   return ((s == null) || (s.length == 0));
}


// Returns true if character c is a digit 
// (0 .. 9).

function isDigit (c)
{   return ((c >= "0") && (c <= "9"));
}


// isFloat (STRING s [, BOOLEAN emptyOK])
// 
// True if string s is an unsigned floating point (real) number. 
//
// Also returns true for unsigned integers. If you wish
// to distinguish between integers and floating point numbers,
// first call isInteger, then call isFloat.
//
// Does not accept exponential notation.
//
// For explanation of optional argument emptyOK,
// see comments of function isInteger.

function isFloat (s)

{   var i;
    var seenDecimalPoint = false;

    if (isEmpty(s)) 
       if (isFloat.arguments.length == 1) return defaultEmptyOK;
       else return (isFloat.arguments[1] == true);

    if (s == decimalPointDelimiter) return false;

    // Search through string's characters one by one
    // until we find a non-numeric character.
    // When we do, return false; if we don't, return true.

    for (i = 0; i < s.length; i++)
    {   
        // Check that current character is number.
        var c = s.charAt(i);

        if ((c == decimalPointDelimiter) && !seenDecimalPoint) seenDecimalPoint = true;
        else if (!isDigit(c)) return false;
    }

    // All characters are numbers.
    return true;
}

/**
* Validates a field of type Numeric to ensure that the user has not left it blank
* and the number is a float type.
*
* Example call: msg += checkFloatField("document.forms[0]","thatField","That Requried Field");
*
* @param	form  		The name of the form in which the field is located (ex: "document.forms[0]").
*		fieldName 	The name of the field you wish to validate.
*    		label		The text label on the form that describes the field to the user.
*
* @return	String tmpMsg.  The validation error message.
*/
function checkFloatField (form, fieldName, label)
{
	var tmpMsg = "";
	hasStyle = eval(form + '.' + fieldName + '.style');
	val = eval(form + '.' + fieldName + '.value');

	// Check to see if a value was entered into the field
	if(!isFloat(val))
	{
		tmpMsg +=" - The field '" + label + "' must contain a numeric value.\n";
		if(hasStyle)
		{
			invalidBorder = "solid 1px red";
			eval(form + '.' + fieldName + '.style.border=invalidBorder');
		}
	}
	else
	{
		if(hasStyle)
		{
			validBorder = "solid 1px #808080";
			eval(form + '.' + fieldName + '.style.border=validBorder');
		}
	}
	return tmpMsg;
}