// 
var bValidateOverride = false;
var bValidateItemOverride = false;


function CheckPage()
{
    if(typeof(Validate) != 'undefined')
    {
        return Validate.Check();
    }
    else
    {
        return true;
    }
}

function Validator()
{
    //debugger;
    //debug_print('Running Validator()');
    var items = new Array();
    this.count=items.length;
    this.Add = Add;
    this.View = View;
    this.Check = Check;
    this.CheckThis = CheckThis;
    
    function Add(control, conditions, messages, runOnCheckAll, runOnBlur, runOnClick, addToBlur, addToMouseOut)
    {
        if(control != null)
        {
            //debugger;
            //debug_print('Running Validator().Add');
            items[items.length] = new ValidatorItem(control, conditions, messages, runOnCheckAll, runOnBlur, runOnClick);
            
            if (addToMouseOut == true)
            {
                control.onmouseout = function(){Validate.CheckThis(this, event)};
                //AddHandler(control.onClick, 'CheckThis(this)');
            }
            if (addToBlur == true)
            {
                control.onblur = function(){Validate.CheckThis(this, event)};
                //AddHandler(control.onClick, 'CheckThis(this)');
            }
        }
        
    }
    
    
    function ValidatorItem(control, conditions, messages, runOnCheckAll, runOnBlur, runOnClick)
    {
        this.control = control;
        this.rules = new Array();
        
        for(var ruleIndex = 0; ruleIndex < conditions.length; ruleIndex++)
        {
            this.rules[this.rules.length] = new ValidatorRule(conditions[ruleIndex], messages[ruleIndex], runOnCheckAll[ruleIndex], runOnBlur[ruleIndex], runOnClick[ruleIndex]);
        }
        
    }

    function ValidatorRule(condition, message, runOnCheckAll, runOnBlur, runOnClick)
    {
        this.condition = condition;
        this.message = message;
        this.runOnCheckAll = runOnCheckAll;
        this.runOnBlur = runOnBlur;
        this.runOnClick = runOnClick;
    }
    
    function View()
    {
        //debug_print('Running Validator().View');
        for(var iLoop=0;iLoop < items.length; iLoop++)
        {
            //debug_print (items[iLoop][0].id);
        }        
    }
    
    function Check()
    {    
        return CheckThis(null, null);
    }

    function CheckThis(checkcontrol, e)
    {
        //debugger;
	    //Richard: TODO: please add onblur checking when doing a submit (checking all controls)...
        var focusId;
        var eventType  = '';
        if((e)&&(e != null))
        {
			eventType = e.type;
		}
        //Clear the alternativeFocusId
        alternativeFocusId = null;
        if (bValidateOverride)
        {
            //debug_print('Validation override in place. Skipping validation');
            return true;
        }
        else if((bValidateItemOverride) && (checkcontrol != null))
        {
            return false;
        }
        else if ((messageArea)&&(messageArea.messageRaised))
        {
            return false;
        }
        
        for(var iLoop=0;iLoop < items.length; iLoop++)
        {
            //debug_print('Validating : items'+[iLoop]);
            if(items[iLoop].control != null)
            {
                if ((checkcontrol == null)||(items[iLoop].control.id==checkcontrol.id))
                {
                    //debug_print('Validating : '+items[iLoop][0].id);
                    for(var iCondition=0;iCondition < items[iLoop].rules.length; iCondition++)
                    {
                         //Very important. 'that' is the name used to identify the object being tested
                        //'that' must be passed in as part of the test so we can use isNAN(that.value) and such like.
                        var that = items[iLoop].control;
                        if((isDisabled(that)==false)&&(isReadOnly(that)==false))
                        {
                            //Check to see if this is an onblur event.
                            //e.g. do not eval an on blur event on checking all controls.
                            if((checkcontrol != null)||(items[iLoop].rules[iCondition].runOnCheckAll == 'true'))
                            {                                
								if(eval(items[iLoop].rules[iCondition].condition))
								{
									//debug_print('Passed : '+items[iLoop][1][iCondition]);
								}
								else
								{
									//Only display a message if one has been defined.
									if(typeof(items[iLoop].rules[iCondition].message) != 'undefined')
									{                        
										if(alternativeFocusId != null)
										{
											focusId = alternativeFocusId;
										}
										else
										{
											focusId = items[iLoop].control.id;
										}
										var msgShown = raiseMessage('validation',items[iLoop].rules[iCondition].message, focusId);
										//debugger;
										return false;
										break;
									}
								}								
                            }
                        }
                    }
                }
            }
            else
            {
                //debug_print('Invalid validation object : items['+iLoop+']');
            }
        }  
        //debugger;
        return true;
    }
    
    function isDisabled(that)
    {
        //Returns true if the control is disabled.
        //else returns false (e.g. if control is not disabled or control does not have a disabled property).
        if(typeof(that.disabled) == 'boolean')
        {
            return that.disabled;
        }
        else
        {
            return false;
        }
    }
    
	function isReadOnly(that)
    {
        //Returns true if the control is readOnly.
        //else returns false (e.g. if control is not readOnly or control does not have a readOnly property).
        if(typeof(that.readOnly) == 'boolean')
        {
            return that.readOnly;
        }
        else
        {
            return false;
        }
    }
}


/********************************************************************************\
 Functions
\********************************************************************************/

function isMatch(strValue, strExpression)
{
    var rgMatch = new RegExp(strExpression);
    return strValue.match(rgMatch)
}

function upperCase(that)
{
    that.value = that.value.toUpperCase();
    return true;
}

function lowerCase(that)
{
    that.value = that.value.toLowerCase();
    return true;
}

function normalCaseFirst(that)
{
    that.value = toNormalCase(that.value,' ', false);
    return true;
}

function normalCaseAll(that)
{
    that.value = toNormalCase(that.value,' ', true);
    return true;
}

function compareDate(strdate_1, strdate_2, strmode)
{
    //debugger;
    var ret_val = false;
    if(
        typeof(strdate_1) != 'undefined' && 
        typeof(strdate_2) != 'undefined' &&
        strdate_1 != '' &&
        strdate_2 != ''
    )
    {
        //This should really check for valid dates either before or after we have created the date objects.
        var new_date_1=toDate(strdate_1);
	    var new_date_2=toDate(strdate_2);
        switch (strmode)
        {
            case "greater":
                ret_val = new_date_1 > new_date_2;
                break;
            case "less":
                ret_val = new_date_1 < new_date_2;
                break;
            case "equal":
                ret_val = new_date_1 == new_date_2;
                break;
            case "equgreater":
                ret_val = new_date_1 >= new_date_2;
                break;
            case "equless":
                ret_val = new_date_1 <= new_date_2;
                break;
            default:
                //No mode so return false.
                ret_val = false;
                break;
        }
    }
    else
    {
        return true;
    }
    return ret_val;
}

function toNormalCase(this_string, word_seperator, all_words)
{
/*
*toNormalCase sets the first letter of one or more words to capital
*
* this_string    - string ('')     - The string to be capitalised
* word_seperator - string (' ')    - Character between words 
* all_words      - boolean (false) - False capitalises first word only, true capitalises all words
*/
    //Init vars
    var first_letter = new String();
    var other_letters = new String();
    var temp_string = new String();
    //check parameters
    if (word_seperator==null)
    {
        word_seperator = ' ';
    }
    if (all_words!=true)
    {
        all_words=false
    }
    this_string = this_string.toLowerCase();
    //All words or just the first?
    if (all_words)
    {
        //Capitalise all words
        var temp_words = new Array();
        temp_words = this_string.split(word_seperator);
        var word_num = 0;
        //Iterate through words
        for (word_num = 0; word_num<temp_words.length; word_num++)
        {
            first_letter = temp_words[word_num].charAt(0);
            other_letters = temp_words[word_num].substring(1,temp_words[word_num].length);
            first_letter = first_letter.toUpperCase();
            if (temp_string=='')
            {
                temp_string += first_letter + other_letters
            }
            else
            {
                temp_string += word_seperator + first_letter + other_letters
            }
        }
    }
    else
    {
        //Capitalise first word only
        first_letter = this_string.charAt(0);
        other_letters = this_string.substring(1,this_string.length);
        first_letter = first_letter.toUpperCase();
        temp_string = first_letter + other_letters
    }
    return (temp_string);
}

function isMaxLength(that, maxLength)
{
    if (that.value.length > maxLength)
        that.value = that.value.substring(0, maxLength)
}

function isValidDecimalPercent(that, min, max)
{
    /*
    Returns a boolean based on whether the value passed in is a number and is between the min and max values.
        true - if all criteria were met
        false - if any of the criteria were not met. 
    */
    var return_value = true;
    if (isNaN(that))
    {
		return_value = false;
    }
    else
    {
        if (that > max || that < min)
        {
            return_value = false;
        }
        if (that.indexOf('.')>-1)
        {
            var this_value = that.toString();
            var value_array = new Array();
            value_array = this_value.split('.');
            debug_print(value_array.length);
            if (value_array.length > 0)
            {
                var decimal_part = value_array[1].toString();
                debug_print(decimal_part);
                if (decimal_part.length > 2)
                {
                    return_value = false;
                }
            }
        }
    }
    return return_value;
}

function keyUpHandler(e)
{
	var kCode = (window.event) ? event.keyCode : e.keyCode; 
    var Esc = (window.event) ? 27 : e.DOM_VK_ESCAPE // MSIE : Firefox
    var Enter = (window.event) ? 13 : e.DOM_VK_ENTER // MSIE : Firefox
    var Tab = (window.event) ? 9 : e.DOM_VK_TAB // MSIE : Firefox
    debug_print('keyUpHandler | '+kCode);
    switch(kCode)
    {        
        case Tab:
            if (doCheckTab)
            {
                return doCheckTab();
            }
	        break;
        default:
            keyDownHandler(e)
		    break;
    }
}

function keyDownHandler(e)
{
	var kCode = (window.event) ? event.keyCode : e.keyCode; 
    var Esc = (window.event) ? 27 : e.DOM_VK_ESCAPE // MSIE : Firefox
    var Enter = (window.event) ? 13 : e.DOM_VK_ENTER // MSIE : Firefox
    var Tab = (window.event) ? 9 : e.DOM_VK_TAB // MSIE : Firefox
	var Ctrl = (window.event) ? event.ctrlKey : e.DOM_VK_CONTROL // MSIE : Firefox
	debug_print('keyDownHandler | '+kCode);
    switch(kCode)
    {
        case Esc:
            doEscape();
	        break;
        case Enter:
            if(event.srcElement.tagName!='TEXTAREA')
            {
                //debugger;
	            doEnter();
	        }
		    break;
	    case Ctrl:
			//debugger
			switch(event.keyCode)
			{
				case 78:
				    //disable CTRL+N
					return doKeyPressStop();
				break;
			}
		    break;
	    case Tab:
	        if(isFormDisabled())
	        {
	            return doKeyPressStop();
	        }
	        break;
    }
    var ele = event.srcElement;
    //disable backspace except in input
    if(
		event.keyCode==8
		&&
		( 
			(ele.tagName.toUpperCase() != 'INPUT' && ele.tagName.toUpperCase() != 'TEXTAREA') 
			|| ele.readOnly == true
			|| ele.type == 'radio'
		)
	)
    {
        return doKeyPressStop();
    }
    
}

function doKeyPressStop()
{
	event.cancelBubble = true;
	event.returnValue = false;
	event.keyCode = false; 
	return false;
}

function doEscape()
{
    var bWarning = false;
    var frMsg ;
    var txtControl;
    switch (self)
    {
         case parent.frames['main']:
			if (document.getElementById('divMainProtect'))
			{
				if (document.getElementById('divMainProtect').style.width != '0px')
				{
					if (parent.frames['message'].__doPostBack)
					{
						parent.frames['message'].__doPostBack('btnMsgCancel','');
					}
				}
			}
			if (parent.frames['main'].__doPostBack)
			{
				frMsg  = parent.frames['message']
				if (frMsg ) { 
				    txtControl = frMsg.document.getElementById('txtValidateCtrl') 
				    if (txtControl) { 
				        if (txtControl.value != '') { 
                            bWarning = true;
				        }
				    }
				}
				if (bWarning) {
				    parent.frames['message'].__doPostBack('btnMsgCancel','');
				} else {
                    parent.frames['main'].__doPostBack('buttonbar:btnCancel','');
                }
	        }
	        break;
        case parent.frames['message']:
            if (parent.frames['message'].__doPostBack)
            {
                parent.frames['message'].__doPostBack('btnMsgCancel','');
            }
	        break;
        case parent.frames['menu']:
            if (parent.frames['main'].__doPostBack)
			{
				frMsg  = parent.frames['message']
				if (frMsg ) { 
				    txtControl = frMsg.document.getElementById('txtValidateCtrl') 
				    if (txtControl) { 
				        if (txtControl.value != '') { 
                            bWarning = true;
				        }
				    }
				}
				if (bWarning) {
				    parent.frames['message'].__doPostBack('btnMsgCancel','');
				} else {
                    parent.frames['main'].__doPostBack('buttonbar:btnCancel','');
                }
			}
            break;
    }
}

function doEnter()
{
    //tries to work out what should be done with 
	if (document.getElementById('buttonbar_imgOk'))
	{
		if (document.getElementById('buttonbar_imgOk').disabled)
		{
			return doKeyPressStop();
		}
	}
	if (parent.frames['message'])
	{
		if (parent.frames['message'].document.getElementById('txtValidateCtrl'))
		{
			if (parent.frames['message'].document.getElementById('txtValidateCtrl').value!='')
			{
				return doKeyPressStop();
			}
		}
		else
		{
			return doKeyPressStop();
		}
	}			
	if (validateWholePage()==0)
	{
		if (parent.frames['main'])
		{
			if (parent.frames['main'].__doPostBack)
			{
				parent.frames['main'].__doPostBack('buttonbar:btnOk','');
			}
		}
		else if (self.__doPostBack!=undefined)
		{
			self.__doPostBack('btnOk','');
		}
	}
}

function doCheckTab()
{
	//Restrains the tab indexing to important areas.
	if(parent.frames['main'])
	{
        if (parent.frames['main'].document.getElementById('divMainProtect'))
	    {
		    /*
		    If the Main area is protected then a message is in place.
		    So don't let tab operate.
		    */
		    if (parent.frames['main'].document.getElementById('divMainProtect').style.width =='100%')
		    {
			    debug_print('doCheckTab: protection in place : '+parent.frames['main'].document.getElementById('divMainProtect').style.width);
			    return doKeyPressStop();
		    }
	    }
	}
    if (self.name=='main')
    {
        //Normal operation, using tabindex-1 to control where tab is allowed
        debug_print('doCheckTab : Normal tab indexing being used. located in frame '+self.name+'.');
        return true;
    }
    else
    {
        if(parent.frames['main'])
        {
	        var tab_value=1;
            var these_controls = self.parent.frames['main'].document.getElementsByTagName('input');
            for (iCtl=0; iCtl<these_controls.length; iCtl++)
            {
		        debug_print('doCheckTab ID :'+these_controls[iCtl].id+' | Class: '+these_controls[iCtl].className);
                if (
					(these_controls[iCtl].type=='text' || these_controls[iCtl].type=='password' || these_controls[iCtl].type=='radio') 
					&& these_controls[iCtl].tabIndex >= tab_value
					&& these_controls[iCtl].readOnly == false
					&& these_controls[iCtl].disabled == false
				)
                {
					try
					{
	                    these_controls[iCtl].focus();
	                    return true;
	                    debug_print('doCheckTab |focusID :'+these_controls[iCtl].id+' | Class: '+these_controls[iCtl].className);
					}
					catch(e)
					{
						debug_print('doCheckTab |failed focusID :'+these_controls[iCtl].id+' | Class: '+these_controls[iCtl].className);
					}
                }
                else
                {
					debug_print('doCheckTab \'not used\' |ID :'+these_controls[iCtl].id+' | Class: '+these_controls[iCtl].className);
                }
            }
        }
    }
}

function isNumeric(expression)
{
    var validChars = "0123456789.";
    var validSignChars = "-+";
    var charValue;
    var decimalPointCount = 0;
    if((expression != null)&&(expression != 'undefined'))
    {
        for (var charIndex = 0; charIndex < expression.length; charIndex++) 
        { 
            charValue = expression.charAt(charIndex); 
            if (validChars.indexOf(charValue) == -1) 
            {
                //This may have a sign operator
                if (!((charIndex==0)&&(validSignChars.indexOf(charValue) != -1)))
                {
                    return false;
                }   
            }
            if(charValue=='.')
            {
                decimalPointCount++;
            }
        }
        if(decimalPointCount<2)
        {
            return true;
        }
        return true;
    }
    else
    {
        return false;
    }
}

//Nick
function isGenericPhoneNo(strPhone)
{
    // Check for correct phone number
    rePhoneNumber = new RegExp(/^\+?\d[-\s\d]*\d$/);

    if (strPhone == '')
    {
        return true;
    }
    
    if (!rePhoneNumber.test(strPhone)) 
    {
      return false;
    }
 
    return true;
    

    //return isMatch(strPhone,'/^\+?\d[-\s\d]*\d$/')

}

//orv
function isEmail(strEmail)
{
    // Check for valid email address
    reExp = new RegExp(/^([a-zA-Z0-9_\.\-])+\@(([a-zA-Z0-9\-])+\.)+([a-zA-Z0-9]{2,4})+$/);

    if (strEmail == '')
    {
        return true;
    }
    
    if (!reExp.test(strEmail)) 
    {
      return false;
    }
 
    return true;

}

function isDate(strDate)
{
	//return !isNaN(new Date(p_Expression));		// <<--- this needs checking
	/* 
	checked, this does not work. or at least not in my tests
	*/
	/*try this
	    known issues:
	        haven't tested all date formats supported
	*/
	if (bValidateOverride)
    {
        debug_print('Validation override in place. Skipping validation');
        return true;
    }
    /*
        This could be extended to be from a passed in format parameter instead of 'hardcoded' to dd/mm/yyy.
    */
    // order of d/m/y - 0/1/2
    var iDay = 0;
    var iMonth = 1;
    var iYear = 2;
    // splitChar - Default to nothing, this would make it fail if it is left, however if no split char is matched later the function returns false anyway..
    var splitChar = ''; 
    // declaration of our regexp for use later.
    var validformat;
    /*These regexp's force a format of 
        [0][1->9] or 1[0->9] or 2[0->9] 3[0-1] for the day
        [0][1-9] or 1[0->2] for the month
        1[000->999] or 2[000->999] for the year
        This has been changed now to make the leading 0's optional in all relevant places.
        Needs to be heavily tested with many dates and formats.
        Supported should be
        01/01/2006
        1/1/2006
        01.01.2006
        1.1.2006
        01-01-2006
        1-1-2006
        01\01\2006
        1\1\2006
    */
    //find SplitChar and set format regexp.
    if (strDate.indexOf('/') >= 0)
    {
        validformat = new RegExp(/(0?[1-9]|[12][0-9]|3[01])(\/)(0?[1-9]|1[0-2])(\/)[129][0-9]{3}/);
        splitChar = '/';
    }
    else if (strDate.indexOf('.') >= 0)
    {
        validformat = new RegExp(/(0?[1-9]|[12][0-9]|3[01])(\.)(0?[1-9]|1[0-2])(\.)[129][0-9]{3}/);
        splitChar = '.';
    }
    else if (strDate.indexOf('-') >= 0)
    {
        validformat = new RegExp(/(0?[1-9]|[12][0-9]|3[01])(\-)(0?[1-9]|1[0-2])(\-)[129][0-9]{3}/);
        splitChar = '-';
    }
    else if (strDate.indexOf('\\') >= 0)
    {
        validformat = new RegExp(/(0?[1-9]|[12][0-9]|3[01])(\\)(0?[1-9]|1[0-2])(\\)[129][0-9]{3}/);
        splitChar = '\\';
    }
    else
    {
        //Failover condition. None of the above matched so return failure.
        return false;
    }
	//debugger;
	if (!strDate.match(validformat))
    {
        //Regexp test, if it fails then return failure.
        return false;
    }
    else
    { 
        //Else process the date further to determine validity as real date.
        //This should be checking for things like feb 29th feb 30th feb 31st.
        var dayfield=strDate.split(splitChar)[iDay]
        var monthfield=strDate.split(splitChar)[iMonth]
        var yearfield=strDate.split(splitChar)[iYear]
        var dayobj = new Date(yearfield, monthfield-1, dayfield)
        if ((dayobj.getMonth()+1!=monthfield)||(dayobj.getDate()!=dayfield)||(dayobj.getFullYear()!=yearfield))
        {
            return false; //alert("Invalid Day, Month, or Year range detected. Please correct and submit again.")
        }
        else
        {
            return true;
        }
    }
    return true;
}

function toDate(expression)
{
    /*
        returns a valid date object.
        expected date format is that of the calendar control.
        e.g. d/m/yyyy
        NOTE: if the date is not valid then this function will return 
        the current date.
        If you need to check date is valid please use isDateValid()
        before calling.
    */
     var sStartDate = expression.split('/');
     var day = 0;
     var month = 0;
     var year = 0;
     if (sStartDate.length > 0)
     {
        day = parseInt(sStartDate[0]);
     }
     if (sStartDate.length > 1)
     {
        month = parseInt(sStartDate[1]);
     }
     if (sStartDate.length > 2)
     {
        year = parseInt(sStartDate[2]);
     }
     if(day == 0)
     {
        day = new Date().getDate();
     }
     if(month == 0)
     {
        month = new Date().getMonth();
     }
     if(year == 0)
     {
        year = new Date().getYear();
     }
     return new Date(year,month,day);
}

// Numeric
// Ahsan 24/10/2006
function numericComparisons(expression, compareValue, whichComparison)
{
    //debugger;
    var value = null;
    var blnComparison = false;
    
    if (expression == '')
    {
        return true;
    }

    if ((expression != null)&&(expression != 'undefined'))
    {
        switch (whichComparison.toLowerCase())
        {
            case 'numericgreaterthanorequalto':
                value = getNumeric(expression, '-.+', true);
                if (value >= compareValue)
                {
                    blnComparison = true;
                }
                break;
                
            case 'numericlessthanorequalto':
                value = getNumeric(expression, '-.+', true);
                if (value <= compareValue)
                {
                    blnComparison = true;
                }
                break;
            
            case 'numericlessthan':
                value = getNumeric(expression, '-.+', true);
                if (value < compareValue)
                {
                    blnComparison = true;
                }
                break;
            
            case 'numericgreaterthan':
                value = getNumeric(expression, '-.+', true);
                if (value > compareValue)
                {
                    blnComparison = true;
                }
                break;
            
            case 'numericnotlongerthan':
                value = getNumeric(expression, '', true);
                if (value.length <= compareValue)
                {
                    blnComparison = true;
                }
                break;
            
            case 'numericnotshorterthan':
                value = getNumeric(expression, '', true);
                if (value.length >= compareValue)
                {
                    blnComparison = true;
                }
                break;
                
            case 'numericlengthequalto':
                value = getNumeric(expression, '', true);
                if (value.length == compareValue)
                {
                    blnComparison = true;
                }
                break;
            
            case 'numericnotblank':
                value = getNumeric(expression, '', true);
                if (value.length > 0)
                {
                    blnComparison = true;
                }
                break;
                
            case 'numericbutnotdecimal':

                value = getNumeric(expression, '+.-', true);
                var intValue = parseInt(value);

                if (value == intValue)
                {
                    blnComparison = true;
                }
                break;
                
            default:
                blnComparison = false;
        }
    }
    else
    {
        blnComparison = false;
    }
    
    return blnComparison;
}

function getNumericValue(that, allowTheseExtras, blnTreatAsANumber)
{
    //debugger;
    that.value = getNumeric(that.value, allowTheseExtras, blnTreatAsANumber);
    return true;
}

// Function: 
//     getNumeric
// Parameters: 
//     expression: input string.
//     allowTheseExtras: chars to be allowed other than numbers.
//     blnTreatAsANumber: will treat expression as a number. when
//     true, allowTheseExtras should only include +, period or a - sign.
// Returns: 
//     Numeric value of expression (input string)
// Example:
//     getNumeric('£  -1.01d', '.', true) will return -1.01
//     getNumeric('£  -1.01.', '.', true) will return false
// Author: 
//     Ahsan 23/10/2006
function getNumeric(expression, allowTheseExtras, blnTreatAsANumber)
{
    //debugger;
    var blnDecimal = false;
    var blnPositiveNegative = false;
    var strExpression = '';
    var chrAtIndex;
    var numList = '0123456789';
    var iCharIndex = 0;
    
    if((expression != null)&&(expression != 'undefined'))
    {
        for (iCharIndex = 0; iCharIndex < expression.length; iCharIndex++) 
        { 
            chrAtIndex = expression.charAt(iCharIndex);
            
           if ((!(numList.indexOf(chrAtIndex) == -1))||(!(allowTheseExtras.indexOf(chrAtIndex) == -1)))
            {
                if (blnTreatAsANumber)
                {
                    if ((chrAtIndex == '.')&&(blnDecimal))
                    {
                        // allow only one decimal occurance.
                        return false;
                    }
                    else if (chrAtIndex == '.')
                    {
                        // first occurrence of decimal
                        blnDecimal = true;
                    }
                    else if (((blnPositiveNegative)&&(chrAtIndex == '-'))||((chrAtIndex == '+')&&(blnPositiveNegative)))
                    {
                        // allow only one occurrence of + or - sign
                        return false;
                    }
                    else if ((chrAtIndex == '-')||(chrAtIndex == '+'))
                    {
                        // first occurance of - or + sign
                        blnPositiveNegative = true;
                    }
                }

                // concat to return string
                strExpression = strExpression.concat(chrAtIndex);

            }
        }

        return strExpression;
    }
    else
    {
        return false;
    }
}